Component of the elastin-associated microfibrils. Forms a ternary complex with BGN and ELN (PubMed:11723132). Interacts with FBN1 (via N-terminal domain) and FBN2 (PubMed:15131124). O-glycosylated; glycans consist of Gal(beta1-3)GalNAc. Forms intermolecular disulfide bonds either with other MAGP-1 molecules or with other components of the microfibrils. Forms transglutaminase cross-links with tropoelastin. Belongs to the MFAP family.