Retinoblastoma 1 protein (RB-1, also retinoblastoma-associated protein, pp110, and p105-Rb) is a 110 kDa tumor suppressor gene and member of the retinoblastoma protein family. Rat RB-1 is 920 amino acids in length. The protein contains a Pocket domain (aa 366-763), which is comprised of two other domains, domain A (aa 366-572) and domain B (aa 632-763), and a “spacer” (aa 573-631). The Pocket domain binds to threonine-phosphorylated domain C (aa 763-920), which thereby prevents interaction with heterodimeric E2F/DP transcription factor complexes. RB-1 is expressed in the retina. The underphosphorylated, active form of RB-1 interacts with E2F1 and represses its transcription activity, leading to cell cycle arrest. Defects in RB-1 lead to the childhood cancer retinoblastoma.
Retinol-binding protein 4 (RBP4) is the specific carrier for retinol (also known as vitamin A), and is responsible for the conversion of unstable and insoluble retinol in aqueous solution into stable and soluble complex in plasma through their tight interaction. As a member of the lipocalin superfamily, RBP4 containing a β-barrel structure with a well-defined cavity is secreted from the liver, and in turn delivers retinol from the liver stores to the peripheral tissues. In plasma, the RBP4-retinol complex interacts with transthyretin (TTR), and this binding is crucial for preventing RBP4 excretion through the kidney glomeruli. RBP4 expressed from an ectopic source efficiently delivers retinol to the eyes, and its deficiency affects night vision largely. Recently, RBP4 as an adipokine, is found to be expressed in adipose tissue and correlated with obesity, insulin resistance (IR) and type 2 diabetes (T2DM).
Regenerating islet-derived protein 3-alpha, also known as Regenerating islet-derived protein III-alpha, REG-3-alpha, REG3A, and HIP, is secreted protein which contains one C-type lectin domain. REG3A is constitutively expressed in intestine, and is a pancreatic secretory protein that may be involved in cell proliferation or differentiation. It is overexpressed during the acute phase of pancreatitis and in some patients with chronic pancreatitis. REG3A and REG1A proteins are both involved in liver and pancreatic regeneration and proliferation. REG3A is also a stress protein involved in the control of bacterial proliferation. REG3A is down-regulated in most primary human gastric cancer cells, and might be useful in the diagnosis of gastric cancer. Additionally, REG3A is a target of beta-catenin signaling in Huh7 hepatoma cells. The REG1A and REG3A are downstream targets of the Wnt pathway during liver tumorigenesis.
Regenerating islet-derived protein 4, also known as REG-like protein, REG4, GISP and RELP, a member of the regenerating gene family belonging to the calcium (C-type) dependent lectin superfamily, has been found to be involved in malignancy in several different organs including the stomach, colorectum, pancreas and prostate. It is highly expressed in the gastrointestinal tract and markedly up-regulated in colon adenocarcinoma, pancreatic cancer, gastric adenocarcinoma, and inflammatory bowel disease. Expression of the Reg4 in different cell types has been associated with regeneration, cell growth and cell survival, cell adhesion and resistance to apoptosis. REG4 protein overexpression is associated with an unfavorable response to preoperative chemoradiotherapy and may be used as a predictive biomarker clinically. REG4 may play an important role in the development and progression of colorectal cancer, as well as in intestinal morphogenesis and epithelium restitution.
Calcium-independent lectin displaying mannose-binding specificity and able to maintain carbohydrate recognition activity in an acidic environment. May be involved in inflammatory and metaplastic responses of the gastrointestinal epithelium.
Inserisci la tua e-mail e seleziona le aree di interesse per ricevere le ultime novità, approfondimenti e promozioni.
Seleziona uno o più ambiti di interesse per ricevere comunicazioni più utili e mirate.
2025 TEMA Ricerca - All Rights Reserved.
