activin

So named for its property of activating FSH secretion. Member of superfamily of proteins that includes TGF-beta, inhibins, & mullerian inhibitory factor. Inhibins & activins inhibit & activate, respectively, secretion of follitropin by the pituitary gland. They are involved in regulating diverse functions, including: - hypothalamic hormone secretion - pituitary hormone secretion - gonadal hormone secretion - germ cell development & maturation - erythroid differentiation - insulin secretion - nerve cell survival - embryonic axial development or bone growth dependent on subunit composition Inhibins appear to oppose the functions of activins. Inhibins are heterodimers of one alpha & one beta subunit Activins are homo- or heterodimers of beta subunits only

Specific

activin A activin AB activin B

General

glycoprotein multisubunit protein secreted protein

Properties

COMPARTMENT: extracellular compartment SECRETED-BY: granulosa cell WITHIN: ovary sertoli cell WITHIN: testis unspecified cell type WITHIN: placenta SUBUNITS: beta-inhibin (2) MOTIF: glycosylation site cysteine-rich region MOTIF: cysteine residue {X+0} MODIFICATION: cysteine residue {X+7} cysteine residue {X+6} MODIFICATION: cysteine residue {X+50} cysteine residue {X+7} MODIFICATION: cysteine residue {X+0} cysteine residue {X+26} MODIFICATION: cysteine residue {X+70} cysteine residue {X+29} MODIFICATION: cysteine residue {X+72} cysteine residue {X+49} MODIFICATION: cysteine residue {X+49} cysteine residue {X+50} MODIFICATION: cysteine residue {X+6} cysteine residue {X+70} MODIFICATION: cysteine residue {X+26} cysteine residue {X+72} MODIFICATION: cysteine residue {X+29}

References

- Matzuk et al Alpha-inhibin is a tumour-suppressor gene with gonadal specificity in mice. Nature 360:313 1992 PMID: 1448148