Intermolecular and interdomain interactions of a dynamin-related GTP-binding protein, Dnm1p/Vps1p-like protein

Dnm1p/Vps1p-like protein (DVLP) is a mammalian member of the dynamin GTPase family, which is classified into subfamilies on the basis of the structura l similarity. Mammalian dynamins constitute the dynamin subfamily. DVLP bel ongs to the Vps1 subfamily, which also includes yeast Vps1p and Dnm1p, Typi cal structural features that discriminate between members of the Vps1 and d ynamin subfamilies are that the former lacks the pleckstrin homology and Pr o-rich domains. Dynamin exists as tetramers under physiological salt condit ions, whereas under low salt conditions, it can polymerize into spirals tha t resemble the collar structures seen at the necks of constricted coated pi ts. In this study, we found that DVLP is also oligomeric, probably tetramer ic, under physiological salt conditions and forms sedimentable large aggreg ates under low salt conditions. The data indicate that neither the pleckstr in homology nor Pro-rich domain is required for the self-assembly. Analyses using the two-hybrid system and coimmunoprecipitation show that the N-term inal region containing the GTPase domain and a domain (DVH1) conserved acro ss members of the dynamin and Vps1 subfamilies, can interact with the C-ter minal region containing another conserved domain (DVH2), The data on the in terdomain interaction of DVLP is compatible with the previous reports on th e interdomain interaction of dynamin, Thus, the self-assembly mechanism of DVLP appears to resemble that of dynamin, suggesting that DVLP may also be involved in the formation of transport vesicles.