| الوصف: |
The control and maintenance of the character, number and protein, carbohydrates and lipid composition of intracellular compartments in a changing environment is one of the fundamental features of a living cell. It is effected, to a large measure, by vesicular traffic which connects the various cellular compartments and handles the transportation of cargo between them. Movement of cargo occurs through a transport system in membrane-bounded containers called vesicles. Vesicles originate at the donor membrane from which they are transported to target organelles where they fuse with the acceptor membrane and deliver their cargo. At the donor site, cytosolic coat proteins or ‘coats’ bind to the donor membrane together with GTP (guanosine 5'-triphosphate)-binding regulatory proteins first to deform a bud, which is then pinched off as a coated vesicle. During budding and targeting events, a number of regulatory proteins interact with the coat components. Currently, several different coat proteins and their adaptor proteins are known. The purpose of this study was to characterize novel components participitating in intracellular vesicle transport. By using computer analysis and EST (expressed sequence tag) database searches, a previously unknown protein was found. Sequencing revealed the presence of a novel protein of 613 amino acids with a calculated molecular mass of 67,149 Da. Based on its structural features, possessing both a VHS domain and an “ear” domain, we named the protein Vear. With its VHS domain in its NH₂ terminus, Vear shows similarity to several endocytosis-associated proteins. With the “ear” domain in its C-terminus, it resembles γ-adaptin, a heavy subunit of the AP-1 complex. Vear mRNA showed a widespread distribution in tissues, with high amounts of mRNA in the kidney, skeletal muscle, and cardiac muscle. At the subcellular level, Vear was localized to the Golgi complex in which it colocalized with the trans-Golgi marker γ-adaptin. The preferential membrane-association was demonstrated by ... |
