Insulin receptor β-subunit (IR β-subunit)

The insulin receptor β-subunit is the transmembrane and intracellular portion of the insulin receptor, a prototypical receptor tyrosine kinase that mediates insulin signaling in target cells[6][7][9][10]. The β-subunit is essential for signal transduction, containing the tyrosine kinase domain that becomes activated upon insulin binding to the extracellular alpha subunit[6][7][8][9][10]. The insulin receptor is a heterotetrameric protein comprising two alpha (α) subunits and two beta (β) subunits. The α-subunit is entirely extracellular and responsible for insulin binding, while the β-subunit spans the membrane and contains both transmembrane and intracellular portions[7][9][10]. The intracellular segment of the β-subunit harbors the receptor’s tyrosine kinase activity, critical for propagating insulin’s effects[6][7][10]. Upon insulin binding to the α-subunit, the β-subunit undergoes autophosphorylation, initiating downstream signaling cascades such as glucose uptake, glycogen synthesis, and inhibition of glucose production[6][7][8].

Other names

INSR β-subunitInsulin receptor beta chainβIRInsulin receptor kinase subunit

Activation/agonism: Insulin or agonists bind the extracellular α-subunit, triggering autophosphorylation of the β-subunit’s cytoplasmic kinase domain and downstream signaling. Tyrosine kinase inhibition: Experimental approaches in research settings