Molecular interactions between dynamin and G-protein betagamma-subunits in neuroendocrine cells

Dynamin and G-proteins both are guanosine triphosphate (GTP) binding proteins, with dynamin active in cellular membrane trafficking and G-proteins in intracellular signal transduction. Here we demonstrate that dynamin physically and functionally interacts with G-protein betagamma-subunits in neuroendocrine GH4C1 cells, on stimulation with thyrotropin-releasing hormone and somatostatin. The interaction appears to be of high affinity and inhibitory on dynamin GTPase activity, mediated by the pleckstrin homology domain and regulated both by the G-protein alpha-subunit and by guanosine nucleotides. Thus, dynamin may target particular sites for receptor-mediated endocytosis by sharing betagamma-subunits with the alpha subunit of G-proteins in neuroendocrine cells.