Crumbs homolog 2 (CRB2) (CRB2)

Crumbs homolog 2 (CRB2) is a transmembrane protein that serves as a master regulator of apical-basal cell polarity and is a member of the evolutionarily conserved Crumbs complex (UniProt P0C6P5). In the mammalian retina, CRB2 is localized to the subapical region of both photoreceptors and Müller glial cells, where it is indispensable for the maintenance of adherens junctions that constitute the external limiting membrane (Pellissier et al., 2014, Hum Mol Genet). Mutations in the CRB2 gene are associated with severe autosomal recessive retinal dystrophies, such as Retinitis Pigmentosa and Leber Congenital Amaurosis, as well as systemic conditions like steroid-resistant nephrotic syndrome (Alves et al., 2014, Invest Ophthalmol Vis Sci; Ebarasi et al., 2015, J Am Soc Nephrol). Therapeutic development primarily focuses on gene augmentation using adeno-associated viral (AAV) vectors to restore CRB2 expression in the retina, which has shown promise in preclinical models for preserving retinal structure and visual function (Buck et al., 2023, Pharmaceutics). However, the therapeutic window is narrow, as both CRB2 deficiency and its overexpression can trigger retinal degeneration, necessitating precise control of transgene levels (Pellissier et al., 2015, Hum Mol Genet). Beyond the eye, CRB2 is vital for podocyte function in the kidney, and its deficiency leads to focal segmental glomerulosclerosis (Ebarasi et al., 2015, J Am Soc Nephrol). Consequently, CRB2 represents a high-potential but technically challenging target for precision genetic medicine.

Other names

Crumbs 2Crumbs-like protein 2CRB2

Gene augmentation therapy to restore functional CRB2 protein levels in retinal photoreceptors and Müller glial cells.