What does retinol-binding protein do?

What does retinol-binding protein do?

To meet vitamin A requirements of tissues, the liver secretes retinol (vitamin A alcohol) into the circulation bound to its sole specific carrier protein, retinol-binding protein (RBP). The single known function of this protein is to transport retinol from the hepatic stores to target tissues.

What type of protein is retinol-binding protein?

Retinol binding protein 4 (RBP4) is a member of the lipocalin family and the major transport protein of the hydrophobic molecule retinol, also known as vitamin A, in the circulation.

Where is retinol-binding protein found?

Retinol-binding protein is most often found bound to transthyretin, but a small, unbound fraction (<10%) passes freely through glomerular membranes and is reabsorbed by renal proximal tubules cells where it is catabolised.

What is RBP in medicine?

Retinol-binding proteins (RBP) are a family of proteins with diverse functions. They are carrier proteins that bind retinol. Assessment of retinol-binding protein is used to determine visceral protein mass in health-related nutritional studies.

Is transthyretin the same as retinol-binding protein?

Retinol transport complex consisting of retinol-binding protein (RBP) and transthyretin (TTR) is involved in the transport of retinol (vitamin A) and thyroxine (T(4)) in the human plasma. RBP is a 21-kDa single polypeptide chain protein, synthesized in the liver, which binds and transports retinol to the target organs.

What is RBP blood test?

Test Details Assess nephritic syndrome and protein-losing enteropathy. Due to the short half-life of approximately 12 hours, RBP may be suitable for monitoring the nutritional status and efficacy of parenteral nutrition.

What is RBP molecular biology?

RNA-binding proteins (often abbreviated as RBPs) are proteins that bind to the double or single stranded RNA in cells and participate in forming ribonucleoprotein complexes. Eukaryotic cells encode diverse RBPs, approximately 500 genes, with unique RNA-binding activity and protein–protein interaction.

What is e vitamin D binding DBP?

DBP, as its name suggests, is the major binding/transport protein for all vitamin D metabolites. There is only a single binding site in its A domain. Vitamin D is produced in the skin by photochemical transformation of 7-dehydrocholesterol (7DHC) into pre-vitamin D, followed by slow equilibrium with vitamin D itself.

What cell releases retinol bound to retinol-binding proteins?

Volume 1. Retinol is bound to retinol-binding protein (RPB) for transport through the circulation. Upon reaching its target tissue, defined by the presence of STRA6 receptors on the cell surface, retinol is released from RPB and binds instead to cellular retinol-binding protein (CRBP).

What are TTR levels?

The major site of serum TTR synthesis is liver with normal concentration in the range of 0.2–0.4 mg/ml and half-life of 2 days. In central nervous system, TTR is expressed in choroid plexus and is released into the cerebrospinal fluid with concentration in the range of 0.02–0.04 mg/ml (Soprano et al., 1985).

What is TTR cardiac amyloidosis?

ATTR amyloidosis is caused by a protein called transthyretin, or TTR, that changes its shape and forms into fibrous clumps. These clumps of misshapen protein are deposited into various organs and peripheral nerves, which can cause them to function abnormally.

Is transthyretin the same as retinol binding protein?

What is the function of retinol binding protein?

Retinol-binding protein (RBP) is a 21-kDa protein that is hepatically synthesized and responsible for transporting vitamin A from the liver to other tissues. It is freely filtered by the glomerulus and subsequently reabsorbed and catabolized by the proximal tubule.

What is retinol used for?

Retinol is the fat soluble vitamin retinol. Vitamin A binds to and activates retinoid receptors (RARs), thereby inducing cell differentiation and apoptosis of some cancer cell types and inhibiting carcinogenesis. Vitamin A plays an essential role in many physiologic processes, including proper functioning of the retina,…

What is the half life of retinol binding protein?

Retinol-binding protein transports retinol and is linked with serum prealbumin in a constant molar ratio. The half-life of retinol-binding protein is about 10 hours and, as with serum prealbumin, it has a small body pool and is a more specific marker of subtle changes in protein stores.

What is retinol and derivatives?

Retinol and derivatives of retinol that play an essential role in metabolic functioning of the retina, the growth of and differentiation of epithelial tissue, the growth of bone, reproduction, and the immune response.