tailieunhanh - Báo cáo khoa học: The Vps4 C-terminal helix is a critical determinant for assembly and ATPase activity and has elements conserved in other members of the meiotic clade of AAA ATPases

The Vps4 C-terminal helix is a critical determinant for assembly and ATPase activity and has elements conserved in other members of the meiotic clade of AAA ATPasesSorting of membrane proteins into intralumenal endosomal vesicles, mul-tivesicular body (MVB) sorting, is critical for receptor down regulation, antigen presentation and enveloped virus budding. Vps4 is an AAA ATPase that functions in MVB sorting. Although AAA ATPases are oligo-meric, mechanisms that govern Vps4 oligomerization and activity remain elusive. Parimala R. Vajjhala1,2, Chau H. Nguyen1,2, Michael J. Landsberg1, Carol Kistler1,2, Ai-Lin Gan1,2, Glenn F. King1, Ben Hankamer1 and Alan L. Munn1,2,3,4 1 2 3 4 Institute for Molecular Bioscience, The. | ỊFEBS Journal The Vps4 C-terminal helix is a critical determinant for assembly and ATPase activity and has elements conserved in other members of the meiotic clade of AAA ATPases Parimala R. Vajjhala1 2 Chau H. Nguyen1 2 Michael J. Landsberg1 Carol Kistler1 2 Ai-Lin Gan1 2 Glenn F. King1 Ben Hankamer1 and Alan L. Munn1 2 3 4 1 Institute for Molecular Bioscience The University of Queensland Australia 2 ARC SpecialResearch Centre for Functionaland Applied Genomics The University of Queensland Australia 3 Schoolof BiomedicalSciences The University of Queensland Australia 4 Schoolof MedicalScience Griffith University Australia Keywords endocytosis lysosome macromolecular complex membrane traffic vacuole Correspondence A. L. Munn Schoolof MedicalScience Griffith University Gold Coast campus Parklands Drive Southport QLD 4222 Australia Fax 61 7 5678 0789 Tel 61 7 5678 0726 E-mail Received 1 November 2007 revised 10 January 2008 accepted 16 January 2008 doi Sorting of membrane proteins into intralumenal endosomal vesicles mul-tivesicular body MVB sorting is critical for receptor down regulation antigen presentation and enveloped virus budding. Vps4 is an AAA ATPase that functions in MVB sorting. Although AAA ATPases are oligomeric mechanisms that govern Vps4 oligomerization and activity remain elusive. Vps4 has an N-terminal microtubule interacting and trafficking domain required for endosome recruitment an AAA domain containing the ATPase catalytic site and a b domain and a C-terminal a helix positioned close to the catalytic site in the 3D structure. Previous attempts to identify the role of the C-terminal helix have been unsuccessful. Here we show that the C-terminal helix is important for Vps4 assembly and ATPase activity in vitro and function in vivo but not endosome recruitment or interactions with Vta1 or ESCRT-III. Unlike the b domain which is also important for Vps4 assembly the C-terminal helix is not .