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INHBB
Identifiers
Aliases	INHBB, inhibin beta B subunit, inhibin subunit beta B
External IDs	OMIM: 147390; MGI: 96571; HomoloGene: 1654; GeneCards: INHBB; OMA:INHBB - orthologs
Gene location (Human)
Chr.	Chromosome 2 (human)
End	120,351,803 bp
Gene location (Mouse)
Chr.	Chromosome 1 (mouse)
End	119,349,978 bp
RNA expression pattern
	Top expressed in
	pericardium; ; ventricular zone; ; lactiferous duct; ; bronchial epithelial cell; ; subcutaneous adipose tissue; ; mucosa of paranasal sinus; ; abdominal fat; ; ganglionic eminence; ; left lobe of thyroid gland; ; skin of leg;
	Top expressed in
	cervix; ; Gonadal ridge; ; decidua; ; cumulus cell; ; membrana granulosa of ovarian follicle; ; calvaria; ; ventricular zone; ; white adipose tissue; ; ciliary body; ; pineal gland;
	More reference expression data
	More reference expression data
Gene ontology
Molecular function	host cell surface receptor binding; cytokine activity; protein homodimerization activity; hormone activity; protein binding; transforming growth factor beta receptor binding; growth factor activity;
Cellular component	extracellular region; perinuclear region of cytoplasm; cell periphery; extracellular space;
Biological process	regulation of apoptotic process; defense response; cell differentiation; negative regulation of insulin secretion; regulation of MAPK cascade; SMAD protein signal transduction; cell development; cellular response to starvation; positive regulation of pathway-restricted SMAD protein phosphorylation; positive regulation of apoptotic signaling pathway; positive regulation of follicle-stimulating hormone secretion; cellular response to leptin stimulus; oocyte development; positive regulation of ovulation; cellular response to insulin stimulus; ovarian follicle development; negative regulation of follicle-stimulating hormone secretion; fat cell differentiation; activin receptor signaling pathway; regulation of signaling receptor activity; adhesion of symbiont to host cell; response to wounding;
	Sources:Amigo / QuickGO
Orthologs
	3625
	16324
	ENSG00000163083
	ENSMUSG00000037035
	P09529
	Q04999
	NM_002193
	NM_008381
	NP_002184
	NP_032407
	Wikidata
View/Edit Human	View/Edit Mouse

Inhibin, beta B, also known as INHBB, is a protein which in humans is encoded by the INHBB gene.^[5]^[6] INHBB is a subunit of both activin and inhibin, two closely related glycoproteins with opposing biological effects.

Function

Inhibin

Inhibins are heterodimeric glycoproteins composed of an α subunit (INHA) and one of two homologous, but distinct, β subunits (βA or βB, this protein). mRNA for the two subunits has been demonstrated in the testes of adult rats.^[7] Inhibin can bind specifically to testicular interstitial cells throughout development and may be an important regulator of Leydig cell testosterone production or interstitial cell function.^[8]

The inhibin beta B subunit joins the α subunit to form a pituitary FSH secretion inhibitor. Inhibin has been shown to regulate gonadal stromal cell proliferation negatively and to have tumour-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.

Activin

Furthermore, the beta B subunit forms a homodimer, activin B, and also joins with the beta A subunit to form a heterodimer, activin AB, both of which stimulate FSH secretion.^[6]

Tissue distribution

Sections of testicular tissue from rat revealed positive immunoreactivity against anti-inhibin intensely appeared in Leydig cells.^[9] In adult animals, binding of ¹²⁵I inhibin was localized primarily to the interstitial compartment of the testis.^[8] Also, Jin et al., (2001) reported that Leydig cells showed strong positive staining for the inhibin βA subunit in pigs testis.^[10]

Receptors

In situ ligand binding studies have shown that ¹²⁵I inhibin βA binds specifically to Leydig cells throughout rat testis development. These results suggest that inhibin has been considered as a regulator of Leydig cell differentiated function.^[11]^[12] Recently, additional inhibin specific binding proteins were identified in inhibin target tissues, including pituitary and Leydig cells.^[13]^[14] From these receptors betaglycan (the TGF-β type III receptor) and InhBP/p120 (a membrane-tethered proteoglycan) were identified as putative inhibin receptors and they are all present in Leydig cells. However, a faint positive reaction was detected in Leydig cell cytoplasm in rats treated with anise oil.^[9] This may be related to the damaged Leydig cells, as a result of the decreasing of inhibin expression. This may be related to its content of safrole.

Cancer

INHBB gene has been observed progressively downregulated in Human papillomavirus-positive neoplastic keratinocytes derived from uterine cervical preneoplastic lesions at different levels of malignancy. ^[15] For this reason, INHBB is likely to be associated with tumorigenesis and may be a potential prognostic marker for uterine cervical preneoplastic lesions progression. ^[15]