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Familial Parkinson disease (PD) due to the A30P mutation in the SNCA gene encoding alpha-synuclein is clinically associated with PD symptoms. In this first pathoanatomical study of the brain of an A30P mutation carrier, we observed neuronal loss in the substantia nigra, locus coeruleus, and dorsal motor vagal nucleus, as well as widespread occurrence of alpha-synuclein immunopositive Lewy bodies, Lewy neurites, and glial aggregates. Alpha-synuclein aggregates ultrastructurally resembled Lewy bodies, and biochemical analyses disclosed a significant load of insoluble alpha-synuclein, indicating neuropathological similarities between A30P disease patients and idiopathic PD, with a more severe neuropathology in A30P carriers.

Based on a hypothesis that interleukin 1 (IL-1) activity is associated with low back pain (LBP), we investigated relationships between previously described functional IL-1 gene polymorphisms and LBP. The subjects were a subgroup of a Finnish study cohort. The IL-1alpha(C(889)-T), IL-1beta(C(3954)-T) and IL-1 receptor antagonist (IL-1RN)(G(1812)-A, G(1887)-C and T(11100)-C) polymorphisms were genotyped in 131 middle-aged men from three occupational groups (machine drivers, carpenters and office workers). A questionnaire inquired about individual and lifestyle characteristics and the occurrence of LBP, the number of days with pain and days with limitation of daily activities because of pain, and pain intensity, during the past 12 months. Lumbar disc degeneration was determined with magnetic resonance imaging. Carriers of the IL-1RNA(1812) allele had an increased risk of LBP (OR 2.5, 95% CI 1.0-6.0) and carriers of this allele in combination with the IL-1alphaT(889) or IL-1betaT(3954) allele had a higher risk of and more days with LBP than non-carriers. Pain intensity was associated with the simultaneous carriage of the IL-1alphaT(889) and IL-1RNA(1812) alleles (OR 3.7, 95% CI 1.2-11.9). Multiple regression analyses allowing for occupation and disc degeneration showed that carriage of the IL-1RNA(1812) allele was associated with the occurrence of pain, the number of days with pain and days with limitations of daily activities. Carriage of the IL-1betaT(3954) allele was associated with the number of days with pain. The results suggest a possible contribution of the IL-1 gene locus polymorphisms to the pathogenesis of LBP. The possibility of chance findings cannot be excluded due to the small sample size.

Human type III iodothyronine deiodinase (D3) catalyzes the conversion of T(4) to rT(3) and of T(3) to 3, 3'-diiodothyronine (T2) by inner-ring deiodination. Like types I and II iodothyronine deiodinases, D3 protein contains selenocysteine (SeC) in the highly conserved core catalytic center at amino acid position 144. To evaluate the contribution of SeC144 to the catalytic properties of D3 enzyme, we generated mutants in which cysteine (D3Cys) or alanine (D3Ala) replaces SeC144 (D3wt). COS cells were transfected with expression vectors encoding D3wt, D3Cys, or D3Ala protein. Kinetic analysis was performed on homogenates with dithiothreitol as reducing cofactor. The Michaelis constant of T(3) was 5-fold higher for D3Cys than for D3wt protein. In contrast, the Michaelis constant of T(4) increased 100-fold. The D3Ala protein was enzymatically inactive. Semiquantitative immunoblotting of homogenates with a D3 antiserum revealed that about 50-fold higher amounts of D3Cys and D3Ala protein are expressed relative to D3wt protein. The relative substrate turnover number of D3Cys is 2-fold reduced for T(3) and 6-fold reduced for T(4) deiodination, compared with D3wt enzyme. Studies in intact COS cells expressing D3wt or D3Cys showed that the D3Cys enzyme is also active under in situ conditions. In conclusion, the SeC residue in the catalytic center of D3 is essential for efficient inner-ring deiodination of T(3) and in particular T(4) at physiological substrate concentrations.

BACKGROUND: The authors identified the second known mutation in the alpha-synuclein(SNCA) gene, an alanine-to-proline exchange in amino acid position 30 (A30P), that cosegregates with the disease in one German family with autosomal dominantly inherited parkinsonism (ADP). The authors studied carriers of the A30P mutation to compare the phenotype of this mutation with idiopathic PD (IPD) and to assess nigrostriatal dopaminergic function in symptomatic and preclinical mutation carriers. METHODS: The pedigree of the A30P family spans five generations with five affected individuals. The authors performed detailed neurologic examinations followed by mutation analysis in 11 living individuals. In three mutation carriers, two individuals with definite PD and one person at risk for PD, they used L-[18]F-fluoro-3,4-dihydroxyphenylalanine (F-DOPA), [11]C-raclopride (RAC), and [18]F-fluorodeoxyglucose (FDG) PET to investigate presynaptic dopaminergic function, dopamine D2 receptors, and cerebral energy metabolism. The authors studied the cognitive functions of carriers of the A30P mutation using neuropsychological screening. RESULTS: PET studies revealed striatal presynaptic dopaminergic alterations consistent with sporadic IPD in two affected family members and no evidence for nigrostriatal dopaminergic dysfunction in one presymptomatic mutation carrier. Neuropsychological testing in four mutation carriers provided evidence for cognitive impairment as a frequent and early symptom of the A30P mutation; this is also supported by regional cerebral energy metabolism alterations in the clinically presymptomatic subject. CONCLUSIONS: The phenotype of the A30P mutation in the SNCA gene is similar to that of sporadic IPD, including a high variability of the age at disease onset, ranging from 54 to 76 years. The follow-up of presymptomatic carriers of the A30P mutation may give insight into preclinical disease stages and early manifestations of PD.

This paper focuses on the amino acid sequence 708-TGDGVNDSPALKK in pig kidney Na,K-ATPase as one of the best conserved among P-type ATPases. In Ca-ATPase this sequence forms a strand-loop-helix structure as part of a Rossman fold next to the phosphorylation site. Substitution of polar residues in the investigated sequence interfered with high-level accumulation of mutant protein. Mutant alpha1-subunit protein only accumulated in membranes from yeast cells grown at 15 degrees C whereas wild-type protein accumulated at both 15 and 35 degrees C. A systematic screen for the molecular mechanism behind lack of accumulation of mutant protein at 35 degrees C showed that transcription and translation were unaffected by the mutations. To demonstrate in vivo protein folding problems, an unfolded protein response reporter system was constructed in yeast. In this strain, only expression of mutant Na,K-ATPase alpha1-subunit caused induction of the unfolded protein response at 35 degrees C, indicating folding problems in the ER. Lowering the expression temperature to 15 degrees C prevented induction of the unfolded protein response after mutant protein expression, indicating correct folding at this temperature. At the permissive temperature mutant proteins were able to escape the endoplasmic reticulum quality control, reach the plasma membrane, and bind ouabain with high affinity. Since mutants in the 708-TGDGVNDSPALKK segment had a thermo inactivation profile identical to that of wild type, they were classified as temperature-sensitive synthesis mutants. The results indicate that this segment contributes side chains of importance for overall folding and maturation of Na,K-ATPase and all other P-type ATPases.