Takasu H, Jee JG, Ohno A, Goda N, Fujiwara K, Tochio H, Shirakawa M, Hiroaki H. Structural characterization of the MIT domain from human Vps4b.
Biochem Biophys Res Commun 2005;
334:460-5. [PMID:
16018968 DOI:
10.1016/j.bbrc.2005.06.110]
[Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2005] [Accepted: 06/15/2005] [Indexed: 11/19/2022]
Abstract
The microtubule interacting and trafficking (MIT) domain is a small protein module of unknown function that is conserved in proteins of diverse function, such as Vps4, sorting nexin 15 (SNX15), and spastin. One non-synonymous single nucleotide polymorphism was reported, which results in a Ile58-to-Met (I58M) substitution in hVps4b. Here, we have determined the solution structure of the MIT domain isolated from the NH(2)-terminus of human Vps4b, an AAA-ATPase involved in multivesicular body formation. The MIT domain adopts an 'up-and-down' three-helix bundle. Comparison with the sequences of other MIT domains clearly shows that the residues involved in inter-helical contacts are well conserved. The Ile58-to-Met substitution resulted a substantial thermal instability. In addition, we found a shallow crevice between helices A and C that may serve as a protein-binding site. We propose that the MIT domain serves as a putative adaptor domain for the ESCRT-III complex involved in endosomal trafficking.
Collapse