Perlecan: a gem of a proteoglycan.

Perlecan, the main proteoglycan of basement membranes and pericellular spaces, is one of the largest single-chain polypeptides of vertebrate animals. The five modules of perlecan are collated from protein building blocks evolutionarily related to molecules involved in nutrient metabolism, mitogenesis and adhesion. These structural motifs, when translated into multimeric functional units, could be effectively utilized by diverse tissues during development, remodelling or neoplastic growth. The protein is highly conserved across species and the available data indicate that this modular proteoglycan has evolved from ancient ancestors by gene duplication and exon shuffling. The discovery of a related molecule in the nematode C. elegans, and the development of skeletal muscle abnormalities in this animal when the perlecan-like molecule is truncated, opens new avenues of research.