ADAM12

ADAM12, or meltrin alpha, is unusual within the family because it exists as two splice variants: membrane-anchored ADAM12-L and secreted ADAM12-S. Both isoforms proteolyze insulin-like growth factor binding proteins, notably IGFBP-3 and IGFBP-5, modulating IGF bioavailability, and ADAM12-L has been implicated in shedding EGFR ligands and in muscle differentiation, the process from which its meltrin name derives. ADAM12-S is abundantly released from the placenta into maternal serum, where altered levels are associated with preeclampsia and fetal chromosomal abnormalities, making it a studied pregnancy biomarker. Expression is also prominent in muscle and remodeling stromal tissues, and ADAM12-L has been linked to cardiac hypertrophy in experimental models.