Interphotoreceptor Matrix Proteoglycan 2 (IMPG2)

Interphotoreceptor matrix proteoglycan-2 is part of an extracellular complex occupying the interface between photoreceptors and the retinal pigment epithelium in the fundus of the eye.

Kuehn and Hageman (1999) cloned human IMPG2, encoding a novel chondroitin sulfate proteoglycan, which they designated IPM200, from the retinal interphotoreceptor matrix. Acharya et al. (2000) also cloned IMPG2, which they called SPACRCAN, from a human retina cDNA library. The deduced 1,160-amino acid protein contains a large central mucin domain, 3 consensus sites for glycosaminoglycan attachment, 2 epidermal growth factor-like repeats, a putative hyaluronan-binding motif, and a potential transmembrane domain near the C terminus.