Proteine RBP4

Retinol-binding protein that mediates retinol transport in blood plasma (PubMed:5541771). Delivers retinol from the liver stores to the peripheral tissues (Probable). Transfers the bound all-trans retinol to STRA6, that then facilitates retinol transport across the cell membrane (PubMed:22665496).

This protein belongs to the lipocalin family and is the specific carrier for retinol (vitamin A alcohol) in the blood. It delivers retinol from the liver stores to the peripheral tissues. In plasma, the RBP-retinol complex interacts with transthyretin which prevents its loss by filtration through the kidney glomeruli. A deficiency of vitamin A blocks secretion of the binding protein posttranslationally and results in defective delivery and supply to the epidermal cells.

Detected in blood plasma and in urine (at protein level).

Retinal dystrophy, iris coloboma, and comedogenic acne syndrome: A disease characterized by retinal degeneration, ocular colobomas involving both the anterior and posterior segment, impaired night vision and loss of visual acuity. Additional characteristic features include developmental abnormalities and severe acne.

Microphthalmia, isolated, with coloboma, 10: A disorder of eye formation, ranging from small size of a single eye to complete bilateral absence of ocular tissues. Ocular abnormalities like opacities of the cornea and lens, scaring of the retina and choroid, and other abnormalities may also be present. Ocular colobomas are a set of malformations resulting from abnormal morphogenesis of the optic cup and stalk, and the fusion of the fetal fissure (optic fissure).

Belongs to the calycin superfamily. Lipocalin family.

Secreted.