RT Journal Article
SR Electronic
T1 Novel small GTPase subfamily capable of associating with tubulin is required for chromosome segregation
JF Journal of Cell Science
JO J. Cell Sci.
FD The Company of Biologists Ltd
SP 4705
OP 4715
DO 10.1242/jcs.01347
VO 117
IS 20
A1 Okai, Takuro
A1 Araki, Yasuhiro
A1 Tada, Minoru
A1 Tateno, Toshiyuki
A1 Kontani, Kenji
A1 Katada, Toshiaki
YR 2004
UL http://jcs.biologists.org/content/117/20/4705.abstract
AB The small GTPase superfamily, which includes the Ras, Rho/Rac, Rab, Arf and Ran subfamilies, serves as a signal transducer to regulate cell proliferation and differentiation, actin cytoskeleton, membrane trafficking, and nuclear transport. Here, we identify novel GTPases (human Gie1 and Gie2) that form a distinct subfamily of the small GTPases in terms of their sequences and intracellular function. Gie stands for `novel GTPase indispensable for equal segregation of chromosomes', and this subfamily is conserved in multicellular organisms. Expression of dominant-negative Gie mutants in mammalian cells or knockdown of Gie transcripts using RNA interference in Drosophila S2 cells induced abnormal morphology in the chromosome segregation. Gie protein has ability to bind to tubulin and localizes with microtubules on the spindle mid-zone in late mitosis. Furthermore, overexpression of Gie mutants that lack putative effector domains but have tubulin-binding ability induced micronucleus formation. Thus, this is the first report showing that a small GTPase subfamily capable of associating with microtubules might be involved in chromosome segregation.