Localization and variable expression of Gαi2 in human endometrium and Fallopian tubes

Abstract

Background: Heterotrimeric G proteins take part in membrane-mediated cell signalling and have a role in hormonal regulation. This study clarifies the expression and localization of the G protein subunit Gαi2 in the human endometrium and Fallopian tube and changes in Gαi2 expression in human endometrium during the menstrual cycle. Methods: The expression of Gαi2 was identified by Polymerase chain reaction (PCR), and localization confirmed by immunostaining. Cyclic changes in Gαi2 expression during the menstrual cycle were evaluated by quantitative real-time PCR. Results: We found Gαi2 to be expressed in human endometrium, Fallopian tube tissue and in primary cultures of Fallopian tube epithelial cells. Our studies revealed enriched localization of Gαi2 in Fallopian tube cilia and in endometrial glands. We showed that Gαi2 expression in human endometrium changes significantly during the menstrual cycle, with a higher level in the secretory versus proliferative and menstrual phases (P < 0.05). Conclusions: Gαi2 is specifically localized in human Fallopian tube epithelial cells, particularly in the cilia, and is likely to have a cilia-specific role in reproduction. Significantly variable expression of Gαi2 during the menstrual cycle suggests Gαi2 might be under hormonal regulation in the female reproductive tract in vivo. © 2007 Oxford University Press.