p53 abnormalities are not a significant prognostic factor in primary, resected NSCLC when all histologic subtypes are combined, but may be a useful prognosticator for adenocarcinomas. Additional studies are warranted for further evaluation, specifically of adenocarcinomas.
Combined deficiency of coagulation factors V and VIII (F5F8D), an autosomal recessive disorder characterized by coordinate reduction in the plasma levels of factor V (FV) and factor VIII (FVIII), is genetically linked to mutations in the transmembrane lectin ERGIC-53 and the soluble calcium-binding protein MCFD2. Growing evidence indicates that these two proteins form a complex recycling between the endoplasmic reticulum (ER) and the ER-Golgi intermediate compartment and thereby function as a cargo receptor in the early secretory pathway of FV and FVIII. For better understanding of the mechanisms underlying the functional coordination of ERGIC-53 and MCFD2, we herein characterize their interaction by x-ray crystallographic analysis in conjunction with NMR and ultracentrifugation analyses. Inspection of the combined data reveals that ERGIC-53-CRD binds MCFD2 through its molecular surface remote from the sugar-binding site, giving rise to a 1∶1 complex in solution. The interaction is independent of sugarbinding of ERGIC-53 and involves most of the missense mutation sites of MCFD2 so far reported in F5F8D. Comparison with the previously reported uncomplexed structure of each protein indicates that MCFD2 but not ERGIC-53-CRD undergoes significant conformational alterations upon complex formation. Our findings provide a structural basis for the cooperative interplay between ERGIC-53 and MCFD2 in capturing FV and FVIII.MCFD2 | ERGIC-53 | calcium-binding protein | cargo receptor | intracellular lectin C ombined deficiency of coagulation factors V and VIII (F5F8D) is an autosomal recessive disorder characterized by coordinate reduction in the plasma levels of factor V (FV) and factor VIII (FVIII) (1, 2) Extensive genetic analysis of F5F8D patients identified two genes that are associated with this disorder. Genetic mutations in LMAN1 account for approximately 70% of F5F8D families, whereas the remaining 30% families possess mutation in MCFD2 (3, 4). LMAN1 encodes the transmembrane lectin ERGIC-53 (ER-Golgi intermediate compound protein of 53 kDa) (5), which possesses a luminal carbohydrate recognition domain (CRD) with specificity for highmannose-type oligosaccharides (6, 7) and forms dimers or hexamers stabilized by disulfide bonds formed in its stalk domain (5, 8). By contrast, the product of MCFD2 is a soluble luminal protein with two EF-hand Ca 2þ -binding motifs (9). It has been shown that MCFD2 interacts with the CRD of ERGIC-53 in a Ca 2þ -dependent manner (9-11). Accumulating evidence indicates that this complex recycles between the endoplasmic reticulum (ER) and the ER-Golgi intermediate compartment (ERGIC) and thereby functions as a cargo receptor in the early secretory pathway of FV and FVIII (12).To gain a better understanding of the molecular mechanisms underlying the sorting and trafficking of these coagulation factors, it is essential to shed light on the structural basis of the cooperative interplay between ERGIC-53 and MCFD2. The crystallographic data of the CRD of rat ERGIC-53 have revealed that it com...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.