EVI5 is a novel centrosomal protein that binds to α- and γ-tubulin

The human EV15 protein carries a TBC domain indicative of Rab GTPase activating protein (GAP) activity, and an extensive coiled-coil motif in the C-terminal region. EV15 is ubiquitously expressed in adult, fetal, and cancer tissues and exists as two mRNA species resulting from differential use of polyadenylation signals. Western blot analysis suggests that different molecular weight protein species are probably generated by posttranslational modification. FPLC analysis demonstrates that EV15 protein can form dimers and confocal microscopy indicates that EV15, in addition to a diffuse localization in the nucleus, also preferentially localizes to the pericentriolar material in interphase cells. Immunoprecipitation and GST pull-down experiments demonstrate that EV15 exists in complexes with both alpha- and gamma-tubulin. Both interactions are localized to the N-terminal part of the EV15 protein. Thus, EV15 is a novel centrosomal protein with a complex expression pattern and subcellular localization, possibly involved in centrosome stability and dynamics. (c) 2005 Elsevier Inc. All rights reserved.