Rab24 colocalizes and interacts with CtBP/BARS a protein involved in cell cycle progression.

MILITELLO, R.; CORDA, D.; COLOMBO, M. I.

Tucumán, Argentina

Congreso; SAIB; 2009

Rab24 colocalizes and interacts with CtBP/BARS a protein involved in cell cycle progression. R. Militello, D. Corda y M.I. Colombo Rab24 is an atypical member of the Rab GTPase family that presents a reticular perinuclear distribution in interphase cells. We have recently shown that during mitosis Rab24 interacts with microtubules and modulates chromosome segregation and cytokinesis.  Rab proteins are thought to control different functions through the interaction with specific effector molecules.  In a recent publication it has been indicated that Rab24 interacts with CtBP/BARS by a yeast two-hybrid assay. The C terminal-binding protein (CtBP) family functions in the nucleus as co-repressors of transcription and in the cytoplasm as regulators of Golgi fission. Interestingly, depletion of CtBP leads to errors in mitotic chromosome segregation. In the present work we have analyzed the distribution of both proteins and its mutants in transiently transfected cells. In HeLa cells overexpressing CtBPwt, the protein presented a punctate pattern and also we observed aggregates that colocalized with Rab24wt. Similar results were obtained when cells were cotransfected with Rab24 D123I (a dominant negative mutant) suggesting that the nucleotide state of the Rab protein is not critical for association. Preliminary results in our laboratory lead us to hypothesize that Rab24 could be involved in the regulation of mitosis through its association with CtBP.