Rab11 is phosphorylated by classical and novel PKC isoenzymes upon sustained PMA stimulation

PAVAROTTI M; CAPMANY A; COLOMBO, MI; DAMIANI MT

Chubut

Congreso; XLVI Reunión Anual de la Sociedad de Investigación en Bioquímica y Biología Molecular; 2010

SAIB

Bioinformatic analysis showed that Rab11 has high probability of being phosphorylated by different PKC isoforms. In this work, we present evidences that Rab11 is phosphorylated by cytosolic kinases upon phorbol esters stimulation using an in vitro assay. Several purified PKC isoforms directly phosphorylated Rab11 and the results indicate that Rab11 was an adequate substrate for classical PKCa and PKCbII but not PKCbI isoenzymes. In addition, the novel PKCå and PKCç but not PKCä isoforms phosphorylated in vitro Rab11 upon PMA activation, whereas the atypical PKCî isoenzyme was unable to phosphorylate this GTPase. Rab11 was also phosphorylated in vivo in PMA-treated HeLa cells. Interestingly, overexpression of both Rab11 and the different PKC isoforms did not alter transferrin recycling in unstimulated cells. However, a sustained PMA-induced activation resulted in the translocation of the classical PKCa and PKCbII to the endocytic recycling compartment enriched in Rab11 and in the transferrin recycling inhibition. This is the first report showing that Rab11 is differentially phosphorylated by distinct PKC isoenzymes and, that this post-translational modification could be a mechanism for the regulation of intracellular trafficking pathways controlled by Rab11.