title: Role of H(abc) domain in membrane trafficking and targeting of syntaxin 1A.
abstract: Membrane syntaxin plays essential roles in exocytosis in eukaryotic cells. The conservative H(abc) domain in plasma membrane syntaxins implies important roles for syntaxin targeting and function. Our previous study showed H(abc) domain was necessary for the trafficking and cluster distribution of syntaxin 1A on the plasma membrane. Here we identified which of the three domains (H(a), H(b) and H(c)) was essential for Stx1A trafficking and clustering. We found that, in INS-1 cells, the mutant truncated with either H(a), H(b) or H(c) domain could be sorted to the cell surface by a different mechanism compared to that of whole H(abc) truncated mutant. In contrast to wild type Stx1A, none of the mutants showed cluster distribution at the functional sites, suggesting that the physiological localization of Stx1A relies on intact H(abc) domain. Furthermore Munc18-1 is found not to be essential for Stx1A cluster distribution, despite important role in stabilizing membrane delivery of Stx1A.
authors.affiliation: Joint Laboratory of the Institute of Biophysics & Huazhong University of Science and Technology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Junmei
authors.initials: J
authors.lastname: Fan
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Yang
authors.forename: Jingze
authors.initials: J
authors.lastname: Lu
authors.forename: Liangyi
authors.initials: L
authors.lastname: Chen
authors.forename: Pingyong
authors.initials: P
authors.lastname: Xu
mesh_terms: D001665:Binding Sites; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D051938:Munc18 Proteins / Q000737:chemistry; D009154:Mutation; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D050600:SNARE Proteins / Q000378:metabolism; D013499:Surface Properties; D050825:Synaptosomal-Associated Protein 25 / Q000737:chemistry; D050827:Syntaxin 1 / Q000737:chemistry*
chemical_list: D051938:Munc18 Proteins; D050600:SNARE Proteins; D050825:Synaptosomal-Associated Protein 25; D050827:Syntaxin 1