Membrane frizzled-related protein (MFRP)

Membrane frizzled-related protein (MFRP) is a single-pass transmembrane protein belonging to the frizzled-related protein family; it is expressed largely in the retinal pigment epithelium (RPE) and ciliary body of the vertebrate eye[1][2][3][4]. The MFRP protein contains structural domains homologous to frizzled family members, including cysteine-rich, CUB, and low-density lipoprotein receptor domains[2]. It plays a crucial role in regulating the proper localization of several transmembrane proteins at the apical surface of the RPE, notably adiponectin receptor 1 (ADIPOR1) and inward rectifier potassium channel 13 (KCNJ13)[1]. Loss-of-function mutations in MFRP, such as seen in the rd6 mouse model, result in abnormal development of photoreceptor outer segments, defective apical microvilli, impaired phagocytosis by RPE cells, and a spectrum of eye diseases including microphthalmia, nanophthalmos, and progressive retinal degeneration[2][3]. MFRP is encoded by a bicistronic transcript that also encodes C1QTNF5, and the two proteins are co-localized and may interact in the RPE[2][3]. While structurally related to the frizzled protein family, MFRP does not function in canonical Wnt signaling in the context of eye development[2]. There are currently no established interacting drugs or direct mechanisms of action for pharmacological modulation, but MFRP and its pathways are potential therapeutic targets for inherited retinal disorders, including gene therapy approaches[1][3].

Other names

MCOP5NNO2RD6FLJ30570C1QTNF5Membrane-type frizzled-related proteinC1q and TNF related 5CTRP5