Interphotoreceptor matrix proteoglycan 1 (IMPG1)

Interphotoreceptor matrix proteoglycan 1 (IMPG1) is a retina-specific, secreted proteoglycan glycoprotein with a molecular weight of approximately 150 kDa. It contains a central mucin-like domain, a carboxy-terminal EGF-like domain, and two SEA domains (SEA-1 and SEA-2); only the SEA-2 domain exhibits autoproteolysis which is essential for functional maturation[1][2][3]. IMPG1 is a major component of the interphotoreceptor matrix (IPM), the extracellular space that surrounds rod and cone photoreceptors, facilitating vital metabolic and structural functions including support for the photoreceptor structure, mediation of nutrient/retinal transport, and photoreceptor disk turnover[1][2][3]. Mutations in IMPG1 can cause inherited retinal diseases such as retinitis pigmentosa and vitelliform macular dystrophy, often by disrupting protein proteolysis or localization, leading to photoreceptor degeneration and vision loss[1][2][3]. IMPG1, together with its paralog IMPG2, is essential for maintaining normal IPM architecture; loss or mutation of IMPG1 in animal models leads to IPM disruption, abnormal retinal deposits, photoreceptor degeneration, and reduced visual responses[2][3][4].

Other names

IPM150SPACRGP147Interphotoreceptor matrix proteoglycan of 150 kDaSialoprotein associated with cones and rodsRP91VMD4

null (no drugs targeting IMPG1 are established; gene therapy or protein replacement strategies are being considered in preclinical studies)