Inhibitory G protein alpha subunit (Gi alpha) expression and localization during human trophoblast differentiation

Objective: Cyclic adenosine monophosphate (cAMP) participates in the regula tion of processes associated with trophoblast syncytialization. As guanosin e triphosphate (GTP)-binding regulatory proteins (G-proteins) modulate aden ylate cyclase activity, the present study investigated the expression and r egulation of the alpha subunit of inhibitory G protein (Gi alpha) during hu man trophoblast differentiation in vitro. Study Design: Protein levels and the immunolocalization of the protein at a subcellular level were assessed. Results: Expression of Gi alpha protein decreased during syncytialization. Moreover, Gia transmigrated from a predominantly cell membrane-associated to a predominantly perinuclear location during the process. Conclusion: The se results suggest that Gia is regulated and may be implicated in cAMP-depe ndent events during the terminal differentiation of human trophoblasts. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.