Regulation of constitutive cargo transport from the trans-Golgi network to plasma membrane by Golgi-localized G protein betagamma subunits.

ABSTRACT: Observations of Golgi fragmentation upon introduction of G protein ?? (G??) subunits into cells have implicated G?? in a pathway controlling the fission at the trans-Golgi network (TGN) of plasma membrane (PM)-destined transport carriers. However, the subcellular location where G?? acts to provoke Golgi fragmentation is not known. Additionally, a role for G?? in regulating TGN-to-PM transport has not been demonstrated. Here we report that constitutive or inducible targeting of G?? to the Golgi, but not other subcellular locations, causes phospholipase C- and protein kinase D-dependent vesiculation of the Golgi in HeLa cells; Golgi-targeted ?(1)?(2) also activates protein kinase D. Moreover, the novel G?? inhibitor, gallein, and the G??-sequestering protein, GRK2ct, reveal that G?? is required for the constitutive PM transport of two model cargo proteins, VSV-G and ss-HRP. Importantly, Golgi-targeted GRK2ct, but not a PM-targeted GRK2ct, also blocks protein transport to the PM. To further support a role for Golgi-localized G??, endogenous G? was detected at the Golgi in HeLa cells. These results are the first to establish a role for Golgi-localized G?? in regulating protein transport from the TGN to the cell surface.

SUBMITTER: Irannejad R 

PROVIDER: S-EPMC2952241 | biostudies-literature | 2010 Oct

REPOSITORIES: biostudies-literature