MREG

MREG is required for lysosome maturation and support a role for MREG in intracellular trafficking.

Full Name

Melanoregulin

Function

Probably functions as cargo-recognition protein that couples cytoplasmic vesicles to the transport machinery. Plays a role in hair pigmentation, a process that involves shedding of melanosome-containing vesicles from melanocytes, followed by phagocytosis of the melanosome-containing vesicles by keratinocytes. Functions on melanosomes as receptor for RILP and the complex formed by RILP and DCTN1, and thereby contributes to retrograde melanosome transport from the cell periphery to the center. Overexpression causes accumulation of late endosomes and/or lysosomes at the microtubule organising center (MTOC) at the center of the cell. Probably binds cholesterol and requires the presence of cholesterol in membranes to function in microtubule-mediated retrograde organelle transport. Binds phosphatidylinositol 3-phosphate, phosphatidylinositol 4-phosphate, phosphatidylinositol 5-phosphate and phosphatidylinositol 3,5-bisphosphate, but not phosphatidylinositol 3,4-bisphosphate or phosphatidylinositol 4,5-bisphosphate (By similarity).

Required for normal phagosome clearing and normal activation of lysosomal enzymes in lysosomes from retinal pigment epithelium cells (PubMed:19240024).

Required for normal degradation of the lipofuscin component N-retinylidene-N-retinylethanolamine (A2E) in the eye. May function in membrane fusion and regulate the biogenesis of disk membranes of photoreceptor rod cells (By similarity).

Biological Process

Melanocyte differentiation Source: GO_Central
Melanosome localization Source: UniProtKB
Melanosome transport Source: GO_Central
Minus-end-directed organelle transport along microtubule Source: Ensembl
Phagosome maturation Source: UniProtKB

Cellular Location

Lysosome
Lysosome membrane
Plasma membrane
Apical cell membrane
Other locations
Melanosome membrane
Cytoplasmic vesicle membrane
Note: Localizes to the inner segment and basal outer segment of rods in the retina.

PTM

Palmitoylated. Palmitoylation is required to maintain the protein at the melanosome membrane.