Cytokine that acts as a physiological ligand for receptor tyrosine kinases LTK and ALK, leading to their activation (  , ). Cytokine-binding is sufficient to activate LTK . In contrast, ALKAL2-driven activation of ALK is coupled with heparin-binding to ALK . Stimulation of ALK signaling is involved in neural development and regulation of energy expenditure (, ).
Subcellular locations: Secreted, Cell membrane
Following interaction with receptor tyrosine kinase ALK, associates with the cell membrane, membrane-binding is required to activate ALK.
Widely expressed with highest levels in adrenal gland and modest levels in pancreas, testis and uterus.