The G alpha subunit G?8 inhibits proliferation, promotes adhesion and regulates cell differentiation.

ABSTRACT: Heterotrimeric G protein-mediated signal transduction plays a pivotal role in both vegetative and developmental stages in the eukaryote Dictyostelium discoideum. Here we describe novel functions of the G protein alpha subunit G?8 during vegetative and development stages. G?8 is expressed at low levels during vegetative growth. Loss of G?8 promotes cell proliferation, whereas excess G?8 expression dramatically inhibits growth and induces aberrant cytokinesis on substrates in a G?-dependent manner. Overexpression of G?8 also leads to increased cell-cell cohesion and cell-substrate adhesion. We demonstrate that the increased cell-cell cohesion is mainly caused by induced CadA expression, and the induced cell-substrate adhesion is responsible for the cytokinesis defects. However, the expression of several putative constitutively active mutants of G?8 does not augment the phenotypes caused by intact G?8. G?8 is strongly induced after starvation, and loss of G?8 results in decreased expression of certain adhesion molecules including CsA and tgrC1. Interestingly, G?8 is preferentially distributed in the upper and lower cup of the fruiting body. Lack of G?8 decreases the expression of the specific marker of the anterior-like cells, suggesting that G?8 is required for anterior-like cell differentiation.

SUBMITTER: Wu Y 

PROVIDER: S-EPMC3754877 | biostudies-literature | 2013 Aug

REPOSITORIES: biostudies-literature