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Mammalian HMG-CoA reductase (HMGCR), the rate-limiting enzyme of the cholesterol biosynthetic pathway and the therapeutic target of statins, is post-transcriptionally regulated by sterol-accelerated degradation. Under cholesterol-replete conditions, HMGCR is ubiquitinated and degraded, but the identity of the E3 ubiquitin ligase(s) responsible for mammalian HMGCR turnover remains controversial. Using systematic, unbiased CRISPR/Cas9 genome-wide screens with a sterol-sensitive endogenous HMGCR reporter, we comprehensively map the E3 ligase landscape required for sterol-accelerated HMGCR degradation. We find that RNF145 and gp78 independently co-ordinate HMGCR ubiquitination and degradation. RNF145, a sterol-responsive ER-resident E3 ligase, is unstable but accumulates following sterol depletion. Sterol addition triggers RNF145 recruitment to HMGCR via Insigs, promoting HMGCR ubiquitination and proteasome-mediated degradation. In the absence of both RNF145 and gp78, Hrd1, a third UBE2G2-dependent E3 ligase, partially regulates HMGCR activity. Our findings reveal a critical role for the sterol-responsive RNF145 in HMGCR regulation and elucidate the complexity of sterol-accelerated HMGCR degradation. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter)., eLife digest Cholesterol is a fatty molecule that is essential for our health; for example, it is a component of the outer membrane that surrounds every cell in our body. Yet, it also has a reputation for clogging arteries and causing heart attacks and strokes. Our organism can adjust the amount of cholesterol it creates through an enzyme called HMGCR, which is found in all cells. Switching off HMGCR, for instance by taking drugs called statins, reduces the amount of cholesterol made by cells. To regulate the activity of HMGCR, the body uses proteins known as E3 ubiquitin ligases, which can label the enzyme for destruction. However, the identity of the ligases that target HMGCR is a matter of intense debate. Here, Menzies, Volkmar et al. addressed this issue by using an approach called a genome-wide CRISPR forward genetic screen. First, HMGCR was marked inside the cells with a fluorescent tag to watch how its levels change in response to different amounts of cholesterol. Then, each gene in the cell was deleted, and the effects recorded. This allowed Menzies, Volkmar et al. to find the genes responsible for the rapid destruction of HMGCR. The experiments revealed that the E3 ubiquitin ligases RNF145 and gp78 are independently responsible for the degradation of the majority of HMGCR, with a third ligase, Hrd1, getting involved if the first two are absent. In particular, RNF145 builds up when a cell is starved of cholesterol, but it immediately marks HMGCR for destruction once cholesterol becomes more abundant. This ligase can therefore both sense and respond to the amount of cholesterol in a cell, making it a perfect candidate for regulating HMGCR based on what the body needs. Identifying the proteins that adjust the levels of HMGCR sheds light on how a cell controls the amount of cholesterol it creates. This knowledge could be relevant in the fight against the health problems associated with this molecule.

Hypoxia-inducible transcription factors (HIFs) facilitate cellular adaptations to low-oxygen environments. However, it is increasingly recognised that HIFs may be activated in response to metabolic stimuli, even when oxygen is present. Understanding the mechanisms for the crosstalk that exists between HIF signalling and metabolic pathways is therefore important. This review focuses on the metabolic regulation of HIFs by small molecule metabolites and iron, highlighting the latest studies that explore how tricarboxylic acid (TCA) cycle intermediates, 2-hydroxyglutarate (2-HG) and intracellular iron levels influence the HIF response through modulating the activity of prolyl hydroxylases (PHDs). We also discuss the relevance of these metabolic pathways in physiological and disease contexts. Lastly, as PHDs are members of a large family of 2-oxoglutarate (2-OG) dependent dioxygenases that can all respond to metabolic stimuli, we explore the broader role of TCA cycle metabolites and 2-HG in the regulation of 2-OG dependent dioxygenases, focusing on the enzymes involved in chromatin remodelling.

Paredes et al. (1) describe polymerase-δ interacting protein 2 (Poldip2) as a novel regulator of mitochondrial lipoylation through stabilization of Ac-CoA synthetase medium-chain family member 1 (ACSM1). We have several concerns with their proposed model based on the following reasons. Prior mammalian and yeast biochemical studies are not consistent with a significant physiological role for lipoate scavenging in eukaryotes (2, 3). Genetic depletion or germline mutations in de novo lipoic acid synthesis enzymes (LIAS, LIPT1, and LIPT2) result in loss of mitochondrial lipoylation, respiration, and developmental defects in mammals, which are not reversed with exogenous lipoic acid (2 … [↵][1]1To whom correspondence may be addressed. Email: dieckman{at}email.arizona.edu, alexander.kastaniotis{at}oulu.fi, or jan33{at}cam.ac.uk. [1]: #xref-corresp-1-1

BACKGROUND AND OBJECTIVES: The usefulness of the Airway Questionnaire 20 (AQ20) – a short version of the St George’s Respiratory Questionnaire (SGRQ) – to evaluate quality of life (QOL) in asthmatic patients following a hospital admission was assessed.METHODS: At baseline and at six months following the index admission, 135 asthmatic patients were asked to complete the AQ20 and the SGRQ. The patient’s peak flow, number of subsequent asthma exacerbations and number of repeat hospital admissions were also recorded.RESULTS: The AQ20 scores ranged from 0 to 20, with a high score indicating poor QOL. The AQ20 had good coverage, with no obvious ceiling or floor effects. In multiple regression analysis, all three SGRQ components were important in predicting AQ20 scores (R2values were 61.9% and 73.1% for baseline and six-month scores, respectively). The AQ20 was closely correlated with the SGRQ, but not redundant when used together. Bias was low when the retest reliability of the AQ20 was evaluated using the Bland-Altman method, but variation was high (−0.64). Patients with subsequent exacerbations (n=52) had higher AQ20 scores at six-month follow-up (P=0.002). In logistic regression, the AQ20 score was closely associated with the incidence of exacerbations (OR 1.15, 95% CI 1.05 to 1.25), with a similar magnitude of association between the AQ20 and the SGRQ. The AQ20 score did not correlate with peak flow at baseline (r=−0.05; P=0.573) or at six months (r=−0.31; P=0.006), and was not responsive to changes in peak flow (r=−0.06; P=0.583).CONCLUSION: The AQ20 can be substituted for the more complicated SGRQ in the assessment of QOL in patients following a hospital admission for an asthma exacerbation.

Hypoxia Inducible transcription Factors (HIFs) are principally regulated by the 2-oxoglutarate and Iron(II) prolyl hydroxylase (PHD) enzymes, which hydroxylate the HIFα subunit, facilitating its proteasome-mediated degradation. Observations that HIFα hydroxylation can be impaired even when oxygen is sufficient emphasise the importance of understanding the complex nature of PHD regulation. Here, we use an unbiased genome-wide genetic screen in near-haploid human cells to uncover cellular processes that regulate HIF1α. We identify that genetic disruption of the Vacuolar H+ ATPase (V-ATPase), the key proton pump for endo-lysosomal acidification, and two previously uncharacterised V-ATPase assembly factors, TMEM199 and CCDC115, stabilise HIF1α in aerobic conditions. Rather than preventing the lysosomal degradation of HIF1α, disrupting the V-ATPase results in intracellular iron depletion, thereby impairing PHD activity and leading to HIF activation. Iron supplementation directly restores PHD catalytic activity following V-ATPase inhibition, revealing important links between the V-ATPase, iron metabolism and HIFs. DOI: http://dx.doi.org/10.7554/eLife.22693.001, eLife digest Most organisms have developed strategies to survive in low oxygen environments. Central to this response are proteins called Hypoxia Inducible Factors (HIFs), which activate genes involved in energy production and blood vessel growth when oxygen is scarce. When plenty of oxygen is present, HIFs are rapidly broken down. This is important because HIFs have also been linked to the growth and spread of cancers. Oxygen sensing enzymes, termed prolyl hydroxylases, play a principal role in controlling the break down of HIFs when oxygen is abundant. However, the activity of these prolyl hydroxylases can be reduced by changes in the nutrient or iron levels present in the cell. This raises questions about how other cell mechanisms help to control HIF levels. By using a technique called an unbiased forward genetic screen to study human cells, Miles, Burr et al. set out to identify the cellular pathways that regulate HIF levels when oxygen is still abundant. Disrupting a pump called the V-ATPase – which normally helps to break down unwanted proteins by acidifying the cellular compartments where they are destroyed – stabilised HIFs. Moreover, Miles, Burr et al. identified two previously uncharacterised genes that are required for the V-ATPase to work correctly. While the V-ATPase is typically associated with the destruction of proteins, a different, unexpected aspect of its activity is responsible for stabilising HIFs. Blocking activity of the V-ATPase reduces levels of iron inside the cell. This inhibits the activity of the prolyl hydroxylases, resulting in HIFs being activated. Overall, the findings presented by Miles, Burr et al. show key links between oxygen sensing, the use of iron and the V-ATPase. Further work is now needed to investigate how V-ATPase activity affects levels of HIFs found inside cells during diseases such as cancer. DOI: http://dx.doi.org/10.7554/eLife.22693.002

The US11 gene product of human cytomegalovirus promotes viral immune evasion by hijacking the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway. US11 initiates dislocation of newly translocated MHC I from the ER to the cytosol for proteasome-mediated degradation. Despite the critical role for ubiquitin in this degradation pathway, the responsible E3 ligase is unknown. In a forward genetic screen for host ERAD components hijacked by US11 in near-haploid KBM7 cells, we identified TMEM129, an uncharacterized polytopic membrane protein. TMEM129 is essential and rate-limiting for US11-mediated MHC-I degradation and acts as a novel ER resident E3 ubiquitin ligase. TMEM129 contains an unusual cysteine-only RING with intrinsic E3 ligase activity and is recruited to US11 via Derlin-1. Together with its E2 conjugase Ube2J2, TMEM129 is responsible for the ubiquitination, dislocation, and subsequent degradation of US11-associated MHC-I. US11 engages two degradation pathways: a Derlin-1/TMEM129-dependent pathway required for MHC-I degradation and a SEL1L/HRD1-dependent pathway required for "free" US11 degradation. Our data show that TMEM129 is a novel ERAD E3 ligase and the central component of a novel mammalian ERAD complex.

Mitochondrial quality control is essential to maintain cellular homeostasis and is achieved by removing damaged, ubiquitinated mitochondria via Parkin-mediated mitophagy. Here, we demonstrate that MYO6 (myosin VI), a unique myosin that moves toward the minus end of actin filaments, forms a complex with Parkin and is selectively recruited to damaged mitochondria via its ubiquitin-binding domain. This myosin motor initiates the assembly of F-actin cages to encapsulate damaged mitochondria by forming a physical barrier that prevents refusion with neighboring populations. Loss of MYO6 results in an accumulation of mitophagosomes and an increase in mitochondrial mass. In addition, we observe downstream mitochondrial dysfunction manifesting as reduced respiratory capacity and decreased ability to rely on oxidative phosphorylation for energy production. Our work uncovers a crucial step in mitochondrial quality control: the formation of MYO6-dependent actin cages that ensure isolation of damaged mitochondria from the network.

Although cellular proteins conjugated to K48-linked Ub chains are targeted to proteasomes, proteins conjugated to K63-ubiquitin chains are directed to lysosomes. However, pure 26S proteasomes bind and degrade K48- and K63-ubiquitinated substrates similarly. Therefore, we investigated why K63-ubiquitinated proteins are not degraded by proteasomes. We show that mammalian cells contain soluble factors that selectively bind to K63 chains and inhibit or prevent their association with proteasomes. Using ubiquitinated proteins as affinity ligands, we found that the main cellular proteins that associate selectively with K63 chains and block their binding to proteasomes are ESCRT0 (Endosomal Sorting Complex Required for Transport) and its components, STAM and Hrs. In vivo, knockdown of ESCRT0 confirmed that it is required to block binding of K63-ubiquitinated molecules to the proteasome. In addition, the Rad23 proteins, especially hHR23B, were found to bind specifically to K48-ubiquitinated proteins and to stimulate proteasome binding. The specificities of these proteins for K48- or K63-ubiquitin chains determine whether a ubiquitinated protein is targeted for proteasomal degradation or delivered instead to the endosomal-lysosomal pathway.

The Kaposi’s sarcoma-associated herpesvirus-encoded ubiquitin E3 ligase K3 ubiquitinates cell-surface MHC class I molecules (MHC I), causing the internalization and degradation of MHC I via the endolysosomal pathway. K3 recruits the cellular E2 ubiquitin-conjugating enzyme Ubc13 to generate lysine-63–linked polyubiquitin chains on MHC I, leading to the clathrin-mediated endocytosis and lysosomal degradation of MHC I. In this study, we identify a ubiquitin isoleucine-44-alanine mutant (I44A) that inhibits K3-mediated downregulation of MHC I by preventing MHC I polyubiqitination. This E3-specific inhibition by I44A prevents dissociation of the MHC I–K3–Ubc13–ubiquitin complex, allows the in vivo visualization of a transient substrate–E3–E2–ubiquitin complex interaction, and highlights a potential substrate hierarchy between the different MHC I alleles downregulated by K3. The I44A mutant also increases cell-surface MHC I expression in control cells in the absence of K3, predicting the presence of an endogenous E3 ubiquitin ligase required for cell-surface MHC I regulation.

Ubiquitylation of membrane receptors is recognised as a critical post-translational modification, governing their regulation and function. Following ubiquitylation, membrane proteins may be internalised, recycled or degraded via lysosomal or proteasomal pathways. Viruses have appropriated these cellular pathways as a mechanism of immune evasion. RING (really interesting new gene)-CH ubiquitin E3 ligases were initially identified from the Kaposi's associated herpesvirus (KSHV) and their founding members, K3 and K5, downregulate several critical immunoreceptors to prevent detection by the host immune system. K3 promotes formation of lysine-63 linked polyubiquitin chains on MHC Class I, signalling Class I internalisation and endolysosomal degradation. K5 targets multiple immunoreceptors, including MHC Class I, CD86, intracellular adhesion molecule (ICAM) 1 and MHC Class I-related chain (MIC)-A/B, thereby preventing detection from cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. The cellular homologues of K3 and K5, the Membrane Associated RING-CH (MARCH) genes, represent eleven proteins that also appear to be important in the downregulation of membrane receptors. While overexpression of several MARCH genes downregulate cell surface receptors such as MHC Class I, MHC Class II, CD86 and ICAM 1, determining their physiological roles has proved difficult. Elucidating the transcriptional regulation, localisation and trafficking of MARCH genes may provide insights into their cellular functions.

The asparagine hydroxylase, factor inhibiting HIF (FIH), confers oxygen-dependence upon the hypoxia-inducible factor (HIF), a master regulator of the cellular adaptive response to hypoxia. Studies investigating whether asparagine hydroxylation is a general regulatory oxygen-dependent modification have identified multiple non-HIF targets for FIH. However, the functional consequences of this outside of the HIF pathway remain unclear. Here, we demonstrate that the deubiquitinase ovarian tumor domain containing ubiquitin aldehyde binding protein 1 (OTUB1) is a substrate for hydroxylation by FIH on N22. Mutation of N22 leads to a profound change in the interaction of OTUB1 with proteins important in cellular metabolism. Furthermore, in cultured cells, overexpression of N22A mutant OTUB1 impairs cellular metabolic processes when compared to wild type. Based on these data, we hypothesize that OTUB1 is a target for functional hydroxylation by FIH. Additionally, we propose that our results provide new insight into the regulation of cellular energy metabolism during hypoxic stress and the potential for targeting hydroxylases for therapeutic benefit., The oxygen-dependent asparagine hydroxylase FIH regulates the transcription factor HIF during the cellular response to hypoxia. This study suggests that FIH may also contribute to the hypoxia response by affecting cellular metabolism via altered deubiquitinase targeting., Author Summary Hypoxia is a commonly encountered physiologic and pathophysiologic stress to which mammalian cells have evolved an effective adaptive response. This response is governed by a transcription factor termed the hypoxia-inducible factor (HIF). The mechanisms linking the cellular sensing of oxygen levels to HIF activation have been elucidated and involve oxygen-dependent hydroxylation of HIF on proline and asparagine residues by a family of hydroxylases. A key question that remains unclear is the extent to which oxygen-dependent hydroxylation occurs as a functional post-translational modification outside of the HIF pathway. This is key to developing our understanding of whether hydroxylation is a general regulatory modification or one which has specifically evolved for the regulation of HIF. Here, we demonstrate that the deubiquitinase ovarian tumor domain containing ubiquitin aldehyde binding protein 1 (OTUB1) is a target for functional hydroxylation by the FIH hydroxylase. Hydroxylation of OTUB1 by FIH on asparagine residue N22 results in a restriction in its interactome, leading us to hypothesize a possible role for hydroxylation in substrate targeting. Of interest, interactions of OTUB1 with a number of proteins involved in metabolism are altered upon removal of the hydroxylation site—implicating OTUB1 as a possible link between oxygen sensing and the regulation of metabolism.

Book reviewed: Sheldon Stern. Averting ‘the Final Failure’: John F. Kennedy and the Secret Cuban Missile Crisis Meetings. Stanford, CA: Stanford University Press, 2003. 496 pp. Illus. $35.00 (cloth). Alice L. George. Awaiting Armageddon: How Americans Faced the Cuban Missile Crisis. Chapel Hill: University of North Carolina Press, 2003. Illus., notes, bibliography, index. $29.95 (cloth).

AIM: To evaluate the whether screening for cerebral metastases in neurologically intact patients with potentially resectable non-small cell lung cancer patients is both worthwhile and cost-effective. METHODS: We prospectively performed computed tomography (CT) of the head in 105 consecutive patients with potentially resectable lung cancer over an 18-month period. None of these patients had neurological symptoms or signs. RESULTS: Five patients (4.8%) with cerebral metastases were identified using CT. At our institution the financial saving of avoiding five thoracotomies was £45,000, whilst the cost of performing 105 head CTs was £16,000. This represented a substantial saving for the healthcare provider and preserved the quality of life in five patients. CONCLUSIONS: We conclude that screening for cerebral metastases in neurologically intact patients with potentially resectable non small cell lung cancer patients is both worthwhile and cost effective.

(2003). The “China Threat”, National Missile Defense and American public opinion. Defense & Security Analysis: Vol. 19, No. 1, pp. 35-54.

Intramembrane proteolytic cleavage by signal peptide peptidase is required for the turnover of some ER-resident, tail-anchored membrane proteins., The regulated turnover of endoplasmic reticulum (ER)–resident membrane proteins requires their extraction from the membrane lipid bilayer and subsequent proteasome-mediated degradation. Cleavage within the transmembrane domain provides an attractive mechanism to facilitate protein dislocation but has never been shown for endogenous substrates. To determine whether intramembrane proteolysis, specifically cleavage by the intramembrane-cleaving aspartyl protease signal peptide peptidase (SPP), is involved in this pathway, we generated an SPP-specific somatic cell knockout. In a stable isotope labeling by amino acids in cell culture–based proteomics screen, we identified HO-1 (heme oxygenase-1), the rate-limiting enzyme in the degradation of heme to biliverdin, as a novel SPP substrate. Intramembrane cleavage by catalytically active SPP provided the primary proteolytic step required for the extraction and subsequent proteasome-dependent degradation of HO-1, an ER-resident tail-anchored protein. SPP-mediated proteolysis was not limited to HO-1 but was required for the dislocation and degradation of additional tail-anchored ER-resident proteins. Our study identifies tail-anchored proteins as novel SPP substrates and a specific requirement for SPP-mediated intramembrane cleavage in protein turnover.

Background: Multiple steps in the degradation of ubiquitinated proteins by the 26 S proteasome require ATP. Results: The six ATPase subunits of the proteasome function in a cyclic manner. Rates of degradation of ubiquitinated proteins are directly proportional to rates of ATP hydrolysis. Conclusion: A specific number of ATPs are consumed in degrading a ubiquitinated substrate. Significance: Polypeptide structure determines the time required and ATP consumed in degrading ubiquitin conjugates. The degradation of ubiquitinated proteins by 26 S proteasomes requires ATP hydrolysis. To investigate if the six proteasomal ATPases function independently or in a cyclic manner, as proposed recently, we used yeast mutants that prevent ATP binding to Rpt3, Rpt5, or Rpt6. Although proteasomes contain six ATPase subunits, each of these single mutations caused a 66% reduction in basal ATP hydrolysis, and each blocked completely the 2–3-fold stimulation of ATPase activity induced by ubiquitinated substrates. Therefore, the ATPase subunits must function in a ordered manner, in which each is required for the stimulation of ATPase activity by substrates. Although ATP is essential for multiple steps in proteasome function, when the rate of ATP hydrolysis was reduced incrementally, the degradation of Ub5-DHFR (where Ub is ubiquitin and DHFR is dihydrofolate reductase) decreased exactly in parallel. This direct proportionality implies that a specific number of ATPs is consumed in degrading a ubiquitinated protein. When the ubiquitinated DHFR was more tightly folded (upon addition of the ligand folate), the rate of ATP hydrolysis was unchanged, but the time to degrade a Ub5-DHFR molecule (∼13 s) and the energy expenditure (50–80 ATPs/Ub5-DHFR) both increased by 2-fold. With a mutation in the ATPase C terminus that reduced gate opening into the 20 S proteasome, the energy costs and time required for conjugate degradation also increased. Thus, different ubiquitin conjugates activate similarly the ATPase subunit cycle that drives proteolysis, but polypeptide structure determines the time required for degradation and thus the energy cost.

Robert S. McNamara [and Brian Van De Mark,] In Retrospect: The Tragedy and Lessons of Vietnam, NewYork:NewYork Times Books, Random House, 1995. Pp.xviii + 414. $27.50. ISBN 08129–2523–8.

SummaryImmunoproteasomes are alternative forms of proteasomes that have an enhanced ability to generate antigenic peptides. Recently, Seifert and colleagues reported surprising observations concerning the functions of immunoproteasomes and cellular responses to interferon-γ: (1) that immunoproteasomes degrade ubiquitinated proteins faster than the constitutive proteasomes, (2) that polyubiquitin conjugates accumulate after interferon-γ treatment but then are preferentially degraded by immunoproteasomes, and (3) that immunoproteasome deficiency causes the formation of inclusions and more severe experimental autoimmune encephalomyelitis (EAE). In contrast, we find that polyubiquitin conjugates do not transiently accumulate following IFNγ-treatment and that immunoproteasomes do not prevent the formation of intracellular inclusions or protect against EAE. Furthermore, purified 26S constitutive and immunoproteasomes bind ubiquitin conjugates similarly and degrade them at similar rates. We conclude that, although immunoproteasomes can increase the generation of peptides appropriate for MHC class I presentation, they do not degrade ubiquitinated proteins more efficiently than constitutive particles.

James A. Nathan is a former Foreign Service Officer and has also taught at the School of Advanced International Studies of the Johns Hopkins University, the Naval War College, and the University of Delaware. He is now Khalid bin Sultan Eminent Scholar at Auburn University at Montgomery and Executive Director of the Alabama Council on World Affairs. He is the author of several books, most recently United States Foreign Policy Making with J. K. Oliver (1994). His book on Diplomacy and World Order will be published by The Johns Hopkins University Press in 1997.

* Deriziotis, P., André, R., and Smith. D.M. contributed equally to this work * - Prion diseases are associated with the conversion of cellular prion protein (PrP(C)) to toxic β-sheet isoforms (PrP(Sc)), which are reported to inhibit the ubiquitin-proteasome system (UPS). Accordingly, UPS substrates accumulate in prion-infected mouse brains, suggesting impairment of the 26S proteasome. A direct interaction between its 20S core particle and PrP isoforms was demonstrated by immunoprecipitation. β-PrP aggregates associated with the 20S particle, but did not impede binding of the PA26 complex, suggesting that the aggregates do not bind to its ends. Aggregated β-PrP reduced the 20S proteasome's basal peptidase activity, and the enhanced activity induced by C-terminal peptides from the 19S ATPases or by the 19S regulator itself, including when stimulated by polyubiquitin conjugates. However, the 20S proteasome was not inhibited when the gate in the α-ring was open due to a truncation mutation or by association with PA26/PA28. These PrP aggregates inhibit by stabilising the closed conformation of the substrate entry channel. A similar inhibition of substrate entry into the proteasome may occur in other neurodegenerative diseases where misfolded β-sheet-rich proteins accumulate.

The issues that prompted the passing of the War Powers Act will continue to bedevil us again if Congress does not prepare to meet the future with seriously asserted procedures to regularize its relationship to the executive branch regarding a recourse to arms. There were unintended ambiguities and unforeseen exigencies in the original war powers legislation that have confounded systematic application of that act. Also inhibiting Congress has been an acceptance of an incorrect formula-that the War Powers Act 'report" triggers the withdrawal of U.S. troops no later than 90 days after they were first committed. In fact, it is not the report that triggers the 90-day clock, but the military activity itself that starts the 90-day clock, irrespective of any report. An improved War Powers Act would require the executive to provide reports that are more timely and more extensive. It would rethink the obligation that troops return within 90 days. And it would compel more thorough consultations pursuant to any military undertaking. An improved war powers statute would come to grips with the "standing" of Congress in court and the financing of any proposed military undertaking.

A hallmark of the Bush Administration has been its clear and insistent claim that it is for the President to decide if, when, and how arms are to be used as an instrument of policy. This new presidentialism debuted in Christmas of 1989, when President George Bush launched Operation Just Cause against Manuel Noriega of Panama. In the hours preceding the Panamanian expedition, the President did not consult Congress "in every possible instance" as was required by the War Powers Act. Rather, on the day after the invasion, President Bush dispatched a letter to the Senate allowing that he was "providing [his] report" in order to "inform" Congress so that he might be "consistent with" the War Powers Resolution. The reference to the War Powers Resolution was hardly more than an institutional courtesy to the legislature, for, as Mr. Bush explained, he had committed forces "pursuant" to his "constitutional authority with respect to the conduct of foreign relations and as Commander and Chief." In Operation Desert Shield, the President dispatched an immense battle group, over 230,000 troops, to Saudi Arabia while Congress was in its summer recess. Despite the requirement of the War Powers Resolution that the President report in writing within 48 hours "any commitment" of U.S. forces or any "substantial enlargement" of combat forces, President Bush waited for six days to notify Congress. Mr. Bush sent his report to congressional leaders only after the first American deployments actually landed. But, as in the case of Panama, the President announced once again that it was his "desire that Congress be fully informed," and that his letter demonstrated that U.S. policy was being conducted in a fashion "consistent with the War Powers Resolution." The core provision of the War Powers Act-a 90-day time limit on the deployment, if U.S. troops were in danger of seeing "imminent combat" -was neatly finessed. Operation Desert Shield did not bode any real danger for U.S. troops, President Bush contended, since military action was not in any way anticipated. "To the contrary," Mr. Bush stated, "it

Protein modification by one or more ubiquitin chains serves a critical signalling function across a wide range of cellular processes. Specificity within this system is conferred by ubiquitin E3 ligases, which target the substrates. Their activity is balanced by deubiquitylating enzymes (DUBs), which remove ubiquitin from both substrates and ligases. The RING-CH ligases were initially identified as viral immunoevasins involved in the downregulation of immunoreceptors. Their cellular orthologues, the Membrane-Associated RING-CH (MARCH) family represent a subgroup of the classical RING genes. Unlike their viral counterparts, the cellular RING-CH proteins appear highly regulated, and one of these in particular, MARCH7, was of interest because of a potential role in neuronal development and lymphocyte proliferation. Difficulties in detection and expression of this orphan ligase lead us to search for cellular cofactors involved in MARCH7 stability. In this study, we show that MARCH7 readily undergoes autoubiquitylation and associates with two deubiquitylating enzymes - ubiquitin-specific protease (USP)9X in the cytosol and USP7 in the nucleus. Exogenous expression and short interfering RNA depletion experiments demonstrate that MARCH7 can be stabilized by both USP9X and USP7, which deubiquitylate MARCH7 in the cytosol and nucleus, respectively. We therefore demonstrate compartment-specific regulation of this E3 ligase through recruitment of site-specific DUBs.

To evaluate whether follow-up of patients recently discharged from the hospital as a result of acute asthma can be adequately provided by a respiratory specialist nurse compared to a respiratory doctor.Single center, prospective, randomized controlled trial.District general hospital in the United Kingdom.One hundred fifty-four of 373 eligible patients admitted with acute asthma were enrolled into the study from October 2000 to October 2003. All patients16 years of age were eligible for the study. Patients with COPD were excluded.Patients were randomly assigned to receive an initial 30-min follow-up clinic appointment within 2 weeks of hospital discharge with either a specialist nurse or respiratory doctor. This comprised a medical review, patient education, and a self-management asthma plan. Further follow-up was then arranged as was deemed appropriate by the corresponding doctor or nurse. All patients were asked to attend a 6-month appointment.The primary outcome was the number of exacerbations within 6 months of hospital admission. Secondary outcome variables were change in peak flow, quality of life (using the St. George Respiratory Questionnaire (SGRQ) and the Asthma Questionnaire 20 [AQ20]), and clinic attendance.Outcome data were available for 66 patients in the doctor group and 70 patients in the nurse group. There was no difference in the number of patients with exacerbations in the nurse group compared to the doctor group (45.6% vs 49.2%; odds ratio, 0.86; 95% confidence interval [CI], 0.44 to 1.71; p = 0.674). However, a significant proportion of patients in both groups had exacerbations despite hospital outpatient follow-up. There was no difference in quality of life (p = 0.285; mean difference, 0.78; 95% CI, - 0.64 to 2.19 for the AQ20; and p = 0.891; mean difference, 1.08; 95% CI, - 5.05 to 7.21 for SGRQ) or change in peak flow (mean difference between nurse and doctor groups, 1.39 (95% CI, - 3.84 to 6.63; p = 0.122) at 6 months.Follow-up care by a nurse specialist for patients admitted with acute asthma can be delivered equivocally with comparable safety and effectiveness to that given by a doctor.

Skeletal muscle wasting is a debilitating consequence of respiratory disease, particularly well characterised in individuals with chronic obstructive pulmonary disease (COPD). However, it remains controversial whether peripheral muscle dysfunction is an intrinsic part of the respiratory disease process, or a generalised response to multiple atrophy stimuli. Such debate has not only informed the subtleties of pathophysiology, but has also instigated detailed analyses of the molecular mechanisms involved in the induction of muscle atrophy, identifying the ubiquitin–proteasome system (UPS) as the predominant pathway required for the rapid proteolysis seen in muscle wasting. In this issue of Thorax ( see page 113 ), Mainguy et al contribute to our knowledge of muscle weakness in chronic respiratory disease, characterising peripheral muscle function in patients with idiopathic pulmonary arterial hypertension (IPAH).1 Ten WHO functional class II–III patients with IPAH and 10 matched healthy controls underwent exercise capacity assessment, quadriceps strength testing and peripheral muscle morphology analysis. Patients with IPAH demonstrated a lower proportion of type I fibres in vastus lateralis muscle biopsies than healthy controls (38% vs 50%), and this was associated with reduced quadriceps strength and a relatively higher potential for anaerobic metabolism (enzymatic ratio of phosphofructokinase (PFK)/3-hydroxyacyl CoA dehydrogenase (HDAH)). While there was no correlation between the proportion of type I fibres and muscle strength with pulmonary haemodynamic parameters, a positive correlation was demonstrated for peripheral muscle strength and exercise capacity ( R 2=0.42, p=0.04). The authors conclude that peripheral muscle dysfunction may contribute to exercise intolerance in patients with IPAH. With relatively small numbers in the study groups, …

The Cuban missile crisis has been of special interest to those growing numbers of civilians who have a professional interest in the use and management of military power. The successful and determinedly civilian orchestration of the great panoply of persuasion that was brought to bear on the Soviets in the Caribbean seemed to herald an era wherein vastly expanded power, blessedly, had become a relevant, useful, and rational instrument of American policy. The triumphant and apparently lopsided position of the United States in the aftermath of the Cuban crisis reinforced the venerable American hope that a stable international order could be sustained if it were underwritten by America’s readiness to employ effective force. What was novel in contemporary “crisis management,” political science Robert Tucker observed a few years later, was “the intensity of the aspiration to exercise a far greater measure of control…. A growing confidence in the ability… to manage crises [was] accompanied by a growing confidence that force [might] be employed in a regulated manner.”1

Preface - Notes on Contributors - The Heyday of New Strategy: The Cuban Missile Crisis and the Confirmation of Coercive Diplomacy J.A.Nathan - The Cuban Missile Crisis: An Overview R.L.Garthoff - The Crisis of Misperceptions: One More Retrospective Appraisal of the Missile Crisis S.Mikoyan - Reconsidering the Missile Crisis: Dealing with the Problems of the American Jupiters in Turkey B.J.Bernstein - The View from Washington and the View from Nowhere: Cuban Missile Crisis Historiography and the Epistemology of Decision Making L.Chang - The Traditional and Revisionist Interpretations Reevaluated: Why Was Cuba a Crisis? R.N.Lebow - Thirteen Months: Cuba's Perspective on the Missile Crisis P.Brenner - President Kennedy's Decision to Impose a Blockade in the Cuban Missile Crisis: Building a Concensus in the ExComm After the Decision E. Cohn - Before 'The Missiles of October': Did Kennedy Plan a Military Strike Against Cuba? J.Hershberg - The Kennedy-Kruschev Letters: An Overview P.Brenner - Index

There are at least three ways we can describe international political behavior: (1) We can view international relations as taking place in an arena marked by military competition for the scarce commodity named security; (2) we can see international political behavior as a complex set of human interaction, where the ‘high politics’ of military policy is being eroded by the increasing stalemate of power and the emergence of global interdependencies; and (3) we can see international politics as an arena of moral obligation. Each of these views implies a different prognosis of the future. A future world based on power seems, however, little likely, given the diminishing utility of the state to serve traditional security ends and the erosion of the use of force. An increasingly interdependent world is possible, but there is no governmental structure presently developing which seems likely to manage these dependencies. And there is little likelihood the third view will receive sufficient institutional sustenance.