SEARCH

SEARCH BY CITATION

Keywords:

  • Ocular albinism;
  • Lysosome;
  • Endosome;
  • G-protein coupled receptor

Abstract

  1. Top of page
  2. Abstract

Ocular albinism type 1 (OA1) is an X-linked recessive disorder characterized by a severe reduction of visual acuity, and hypopigmentation of the retina that leads to nystagmus, strabismus, and photophobia/photodysphoria. Microscopic examination of both retinal pigment epithelium and skin melanocytes in OA1 reveals the presence of macromelanosomes, suggesting that the OA1 gene product plays a role in melanosome biogenesis. Studies of mutations identified from OA1 patients and an Oa1 knock-out mouse model further implicate OA1 protein function in the late stage of melanosome development. Because its effects are primarily limited to the eye, OA1 represents an ideal model system to study the relationship between pigmentation and visual development. Based upon sequence homology and biochemical studies, OA1 may represent a novel intracellular G-protein coupled receptor. Understanding the function of OA1 will contribute greatly to our understanding of melanosome biogenesis and the role of pigmentation in visual development.

Abbreviations
CHS

Chediak–Higashi syndrome

ER

endoplasmic reticulum

GPCR

G-protein coupled receptor

LE

late endosome

M6PR

mannose-6-phosphate receptor

MMG

melanin macroglobule

OA1

ocular albinism type 1

RPE

retinal pigment epithelium

TGN

trans-Golgi network

TM

transmembrane

TYR

tyrosinase

Tyrp1

tyrosinase-related protein 1