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Abstract

Inhibin binding protein (InhBP/p120), beta-glycan, and the continuing search for the inhibin receptor (PDF) (HTML) 
Bernard,Daniel J.; Chapman,Stacey C.; Woodruff,Teresa K.
Molecular Endocrinology 16(2): 207-212
Publication date: 2002

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Betaglycan (the TGFß type III receptor) and InhBP/p120(a membrane-tethered proteoglycan) were recently identifiedas putative inhibin receptors. Here, we review the current stateof knowledge regarding these two proteins with respect to theirpotential roles in inhibin biology. Importantly, neither proteinappears to satisfy all of the criteria required for classificationas a bona fide inhibin receptor. Betaglycan does not appearto be expressed in pituitary gonadotropes, the primary targetof circulating inhibins, and InhBP/p120 does not bind inhibinsin conventional receptor binding assays. While both proteinsappear capable of promoting inhibin-mediated antagonism of activinsignaling, neither appears to generate inhibin-specific intracellularsignals. Recently, additional inhibin binding proteins wereidentified in inhibin target tissues, including pituitary andLeydig cells. Characterization of these proteins, coupled withongoing investigations of betaglycan and InhBP/p120, will leadto a clearer understanding of mechanisms of inhibin action.

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