INVESTIGADORES
PAVAROTTI Martin Alejandro
artículos
Título:
Rab11 is phosphorylated by classical and novel Protein Kinase C isoenzymes upon sustained phorbol ester activation
Autor/es:
PAVAROTTI MARTÍN A; CAPMANY A; VITALE N ; COLOMBO MI; DAMIANI MT
Revista:
BIOLOGY OF THE CELL
Editorial:
PORTLAND PRESS LTD
Referencias:
Lugar: Londres; Año: 2012 p. 1 - 10
ISSN:
0248-4900
Resumen:
Rab11 is a small GTPase that controls diverse intracellular trafficking pathways but themolecular machinery that regulates the participation of Rab11 in those different transport events ispoorly understood. In resting cells, Rab11 localizes at the endocytic recycling compartment whereas the different Protein Kinase C (PKC) isoforms display a cytosolic distribution. Sustained phorbol ester stimulation induces the translocation of the classical PKCα and PKCβII isoenzymes to the endocytic recycling compartment enriched in Rab11, and results in transferrin recycling inhibition. In contrast, novel PKCε and atypical PKCζ isoenzymes neither redistribute to the perinucleus nor modify transferrin recycling transport after phorbol esters stimulation. Whereas several Rabs have been shown to be phosphorylated, there is no evidence that Rab11 as a kinase substrate yet. In this report, we show that Rab11 appears phosphorylated in vivo in phorbol esters-stimulated cells. A bioinformatic analysis of Rab11 allowed us to identify several high-probability Ser/Thr kinase phosphorylation sites. Our results demonstrate that classical Protein Kinase C (PKCα and PKCβII but not PKCβI) directly phosphorylate Rab11 in vitro. In addition, novel PKCε and PKCη but not PKCδ isoenzymes also phosphorylate Rab11. Mass spectroscopy analysis revealed that Ser 177 is the Rab11 residue to be phosphorylated in vitro by either PKCβII or PKCε. In agreement, the phosphomimetic mutant, Rab11 S177D, retained transferrin at the endocytic recycling compartment in the absence of PMA stimulus. Hence this report shows for the first time that Rab11 is differentially phosphorylated by distinct PKC isoenzymes and that this post-translational modification might be a regulatory mechanism of intracellular trafficking.