Inhibin, beta A, also known as INHBA, is a protein which in humans is encoded by the INHBAgene. INHBA is a subunit of both activin and inhibin, two closely related glycoproteins with opposing biological effects.
The inhibin beta A subunit joins the alpha subunit to form a pituitary FSH secretion inhibitor. Inhibin has been shown to regulate gonadal stromal cell proliferation negatively and to have tumor-suppressor activity. In addition, serum levels of inhibin have been shown to reflect the size of granulosa-cell tumors and can therefore be used as a marker for primary as well as recurrent disease. Because expression in gonadal and various extragonadal tissues may vary severalfold in a tissue-specific fashion, it is proposed that inhibin may be both a growth/differentiation factor and a hormone. Furthermore, the beta A subunit forms a homodimer, activin A, and also joins with a beta B subunit to form a heterodimer, activin AB, both of which stimulate FSH secretion. Finally, it has been shown that the beta A subunit mRNA is identical to the erythroid differentiation factor subunit mRNA and that only one gene for this mRNA exists in the human genome.
^Lewis, K A; Gray P C; Blount A L; MacConell L A; Wiater E; Bilezikjian L M; Vale W (March 2000). "Betaglycan binds inhibin and can mediate functional antagonism of activin signalling". Nature (ENGLAND) 404 (6776): 411–4. doi:10.1038/35006129. ISSN0028-0836. PMID10746731.
^Martens, J W; de Winter J P; Timmerman M A; McLuskey A; van Schaik R H; Themmen A P; de Jong F H (July 1997). "Inhibin interferes with activin signaling at the level of the activin receptor complex in Chinese hamster ovary cells". Endocrinology (UNITED STATES) 138 (7): 2928–36. doi:10.1210/endo.138.7.5250. ISSN0013-7227. PMID9202237.
Munz B, Hübner G, Tretter Y et al. (1999). "A novel role of activin in inflammation and repair.". J. Endocrinol.161 (2): 187–93. doi:10.1677/joe.0.1610187. PMID10320815.CS1 maint: Explicit use of et al. (link)
Welt C, Sidis Y, Keutmann H, Schneyer A (2002). "Activins, inhibins, and follistatins: from endocrinology to signaling. A paradigm for the new millennium.". Exp. Biol. Med. (Maywood)227 (9): 724–52. PMID12324653.
Shao L, Frigon NL, Young AL et al. (1992). "Effect of activin A on globin gene expression in purified human erythroid progenitors". Blood79 (3): 773–81. PMID1310063.CS1 maint: Explicit use of et al. (link)
Tanimoto K, Handa S, Ueno N et al. (1992). "Structure and sequence analysis of the human activin beta A subunit gene". DNA Seq.2 (2): 103–10. doi:10.3109/10425179109039678. PMID1777673.CS1 maint: Explicit use of et al. (link)
Barton DE, Yang-Feng TL, Mason AJ et al. (1989). "Mapping of genes for inhibin subunits alpha, beta A, and beta B on human and mouse chromosomes and studies of jsd mice". Genomics5 (1): 91–9. doi:10.1016/0888-7543(89)90091-8. PMID2767687.CS1 maint: Explicit use of et al. (link)
Sumitomo S, Inouye S, Liu XJ et al. (1995). "The heparin binding site of follistatin is involved in its interaction with activin". Biochem. Biophys. Res. Commun.208 (1): 1–9. doi:10.1006/bbrc.1995.1297. PMID7887917.CS1 maint: Explicit use of et al. (link)
Xu J, McKeehan K, Matsuzaki K, McKeehan WL (1995). "Inhibin antagonizes inhibition of liver cell growth by activin by a dominant-negative mechanism". J. Biol. Chem.270 (11): 6308–13. doi:10.1074/jbc.270.11.6308. PMID7890768.
ten Dijke P, Ichijo H, Franzén P et al. (1993). "Activin receptor-like kinases: a novel subclass of cell-surface receptors with predicted serine/threonine kinase activity". Oncogene8 (10): 2879–87. PMID8397373.CS1 maint: Explicit use of et al. (link)
Tanimoto K, Yoshida E, Mita S et al. (1997). "Human activin betaA gene. Identification of novel 5' exon, functional promoter, and enhancers". J. Biol. Chem.271 (51): 32760–9. doi:10.1074/jbc.271.51.32760. PMID8955111.CS1 maint: Explicit use of et al. (link)