Membrane targeting of p115 phosphorylation mutants and their effects on Golgi integrity and secretory traffic in vivo

BRANDON, E; GAO, Y; GARCIA MATA, R; ALVAREZ, C; SZTUL, E

ELSEVIER GMBH

Año: 2003 vol. 82 p. 411 - 411

he cytosolic phosphoprotein p115 is required for ER to Golgitraffic and for Golgi reassembly after mitosis. In cells, p115 islocalized to ER exit sites, ER-Golgi Intermediate Compartment(ERGIC) and the Golgi, and cycles between thesecompartments. P115 is phosphorylated on serine 942, and thismodification appears to control p115 association with membranes.P115 is likely to function by reversibly interacting witheffector proteins, and in the Golgi, two proteins, GM130 andgiantin, have been shown to bind p115. The GM130-p115 andthe giantin-p115 interactions are enhanced by p115 phosphorylation.Phosphorylation appears to be essential for p115function, since substitutions of serine 942 abolish p115 ability tosustain cisternal reformation in an in vitro assay reconstitutingGolgi reassembly after mitosis. Here, we explored howphosphorylation of p115 affects its intracellular targeting todistinct cellula