Signaling mechanisms and physiological functions of G-protein Gα13 in blood vessel formation, bone homeostasis, and cancer

Heterotrimeric G-proteins are cellular signal transducers. They mainly relay signals from G-protein-coupled receptors (GPCRs). GPCRs function as guanine nucleotide-exchange factors to active these G-proteins. Based on the sequence and functional similarities, these G-proteins are grouped into four subfamilies: G(s), G(i), G(q), and G(12/13). The G(12/13) subfamily consists of two members: G(12) and G(13). G(12/13)-mediated signaling pathways play pivotal roles in a variety of physiological processes, while aberrant regulation of this pathway has been identified in various human diseases. Here we summarize the signaling mechanisms and physiological functions of G alpha(13) in blood vessel formation and bone homeostasis. We further discuss the expanding roles of G alpha(13) in cancers, serving as oncogenes as well as tumor suppressors.