Cytokine that acts as a physiological ligand for receptor tyrosine kinase LTK, leading to its activation (  ). Monomeric ALKAL1 binds to LTK, leading to LTK homodimerization and activation (, ). In contrast to ALKAL2, does not act as a potent physiological ligand for ALK (, ).
Subcellular locations: Secreted, Cell membrane
Following interaction with receptor tyrosine kinase LTK, associates with the cell membrane, membrane-binding is required to activate LTK.
Widely expressed with highest levels in thyroid and moderate levels in stomach, trachea, small intestine, prostate and brain.