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We describe a novel interaction between the disintegrin and cysteine-rich (DC) domains of ADAM12 and the integrin α7β1. Integrin α7β1 extracted from human embryonic kidney 293 cells transfected with α7 cDNA was retained on an affinity column containing immobilized DC domain of ADAM12. 293 cells stably transfected with α7 cDNA adhered to DC-coated wells, and this adhesion was partially inhibited by 6A11 integrin α7 function-blocking antibody. The X1 and the X2 extracellular splice variants of integrin α7 supported equally well adhesion to the DC protein. Integrin α7β1-mediated cell adhesion to DC had different requirements for Mn2+ than adhesion to laminin. Furthermore, integrin α7β1-mediated cell adhesion to laminin, but not to DC, resulted in efficient cell spreading and phosphorylation of focal adhesion kinase (FAK) at Tyr397. We also show that adhesion of L6 myoblasts to DC is mediated in part by the endogenous integrin α7β1 expressed in these cells. Since integrin α7 plays an important role in muscle cell growth, stability, and survival, and since ADAM12 has been implicated in muscle development and regeneration, we postulate that the interaction between ADAM12 and integrin α7β1 may be relevant to muscle development, function, and disease. We also conclude that laminin and the DC domain of ADAM12 represent two functional ligands for integrin α7β1, and adhesion to each of these two ligands via integrin α7β1 triggers different cellular responses. [Copyright &y& Elsevier]

Abstract: We describe biochemical and structural studies of the isolated cystic fibrosis transmembrane conductance regulator (CFTR) protein. Using electron cryomicroscopy, low resolution three-dimensional structures have been obtained for the non-phosphorylated protein in the absence of nucleotide and for the phosphorylated protein with ATP. In the latter state, the cytosolic nucleotide-binding domains move closer together, forming a more compact packing arrangement. Associated with this is a reorganization within the cylindrical transmembrane domains, consistent with a shift from an inward-facing to outward-facing configuration. A region of density in the non-phosphorylated protein that extends from the bottom of the cytosolic regions up to the transmembrane domains is hypothesised to represent the unique regulatory region of CFTR. These data offer insights into the architecture of this ATP-binding cassette protein, and shed light on the global motions associated with nucleotide binding and priming of the chloride channel via phosphorylation of the regulatory region. [Copyright &y& Elsevier]

Morbidity and mortality of lung cancer rank first in China and worldwide. Thus, noninvasive prognostic biomarkers are critical for clinicians to perform risk assessment in lung cancer patients prior to or during the course of treatment. In this study, we evaluated the prognostic value of preoperative hematocrit (HCT) count reduction on the long-term survival of lung cancer patients undergoing pneumonectomy and analyzed the correlation between reduced HCT counts and patients’ clinicopathological features. A total of 1022 patients who underwent surgical treatment in Harbin Medical University Cancer Hospital, China, from February 2006 to December 2013, were enrolled in this study. The association between the clinicopathologic variables and HCT were evaluated by Mann-Whitney U-test and chi-square test, respectively. Survival curves were generated using Kaplan-Meier estimates, and differences between the curves were analyzed by a log-rank test. Multivariable analysis showed that high HCT (P < 0.001, HR: 0.595, 95% CI: 0.458–0.774) was favorable for patients’ survival. Low HCT patients presented shorter mean months of OS than that of high HCT patients (P < 0.001). Male adenocarcinoma carcinoma patients with lower body mass index (BMI) and advanced tumor stage were more likely to observe low HCT. We identified for the first time reduced preoperative HCT count as an independent risk factor leading to poor prognosis in lung cancer patients who underwent surgical treatment. [ABSTRACT FROM AUTHOR]

Cystic fibrosis affects about 1 in 2500 live births and involves loss of transmembrane chloride flux due to a lack of a membrane protein channel termed the cystic fibrosis transmembrane conductance regulator (CFTR). We have studied CFTR structure by electron crystallography. The data were compared with existing structures of other ATP-binding cassette transporters. The protein was crystallized in the outward facing state and resembled the well characterized Sav1866 transporter. We identified regions in the CFTR map, not accounted for by Sav1866, which were potential locations for the regulatory region as well as the channel gate. In this analysis, we were aided by the fact that the unit cell was composed of two molecules not related by crystallographic symmetry. We also identified regions in the fitted Sav1866 model that were missing from the map, hence regions that were either disordered in CFTR or differently organized compared with Sav1866. Apart from the N and C termini, this indicated that in CFTR, the cytoplasmic end of transmembrane helix 5/11 and its associated loop could be partly disordered (or alternatively located). [ABSTRACT FROM AUTHOR]