Anti-ALK and LTK ligand 1 antibodies are used in the immunodetection of the protein encoded by the ALKAL1 gene. In humans, the canonical protein has a reported length of 129 amino acid residues and a mass of 14.3 kDa. Its subcellular localization is in the cell membrane and is also secreted. Alternative splicing is reported to yield 2 different isoforms for this protein. It is reported to be widely expressed with highest levels in thyroid and moderate levels in stomach, trachea, small intestine, prostate and brain. A member of the ALKAL protein family, it is a reported cytokine that acts as a physiological ligand for receptor tyrosine kinase LTK, leading to its activation. Other names for this target antigen include RPLK9433, augmentor beta, augmentor-alpha, family with sequence similarity 150 member A, protein FAM150A, and AUG-beta.