RXRB

Fig1. RXR subtypes are distinctly required to cellular effects promoted by RA-mediated neuronal differentiation. (Carolina Saibro Girardi, 2019)

What is RXRB protein?

RXRB (retinoid X receptor beta) gene is a protein coding gene which situated on the short arm of chromosome 6 at locus 6p21. This gene encodes a member of the retinoid X receptor (RXR) family of nuclear receptors which are involved in mediating the effects of retinoic acid (RA). This receptor forms homodimers with the retinoic acid, thyroid hormone, and vitamin D receptors, increasing both DNA binding and transcriptional function on their respective response elements. The RXRB protein is consisted of 533 amino acids and its molecular mass is approximately 56.9 kDa.

What is the function of RXRB protein?

RXRB protein is a member of the nuclear receptor family, which plays an important role in a variety of biological processes. As a subtype of retinoid X receptor (RXR), RXRB is mainly involved in regulating gene expression and affecting cell differentiation, proliferation and apoptosis. RXRB regulates gene transcription by binding to specific ligands, such as vitamin A derivatives such as retinaldehyde, to form heterodimers that bind to specific sequences on DNA. In addition, RXRB is also involved in the regulation of immune system function, the maintenance of cholesterol metabolism balance, and the development of tumors.

RXRB Related Signaling Pathway

The RXRB protein is a cell surface receptor in the retina that is involved in several signaling pathways, the most important of which is the light signal transduction pathway associated with visual signaling. RXRB regulates light signal transduction in photoreceptor cells by interacting with G protein-coupled receptors (GPCRS), converting light signals into electrical signals, thereby triggering a cascade of visual transmission chains. In addition, RXRB is also associated with other signaling pathways, such as cell proliferation, differentiation, and apoptosis. For example, RXRB can regulate cell cycle progression and influence cell proliferation and differentiation.

RXRB Related Diseases

Abnormal RXRB function may be associated with a variety of diseases. Retinitis pigmentosa is a genetic disorder characterized by progressive degeneration of retinal cells, resulting in loss of vision. In addition, the RXRB protein is also associated with the development of certain eye tumors, such as retinoblastoma and melanoma. The RXRB protein is also involved in the development of other vision-related diseases, such as glaucoma and cataracts.

Case Study 1: Belamy Cheung, 2003

Nuclear retinoid receptors mediate retinoid effects through tissue-specific, ligand-receptor interactions and subsequent transcriptional regulation of secondary target genes. Retinoic acid receptor beta (RARbeta) is itself a retinoid target gene with a retinoic acid response element (betaRARE) in the 5' untranslated region of the RARbeta2 gene. Altered transcriptional regulation of RARbeta may play a role in human carcinogenesis and the retinoid-responsiveness of malignant cells. Here the researchers used retinoid X receptor-specific antibodies in electrophoretic mobility shift assays to show that the retinoid X receptor beta (RXRbeta) protein was recruited to the betaRARE, after retinoid treatment of retinoid-sensitive neuroblastoma (NB), lung and breast cancer cell lines, but not retinoid-resistant lung and breast cancer cell lines. RXRbeta selectively enhanced retinoid-induced transcriptional activation of the betaRARE. Stable overexpression of RXRalpha and RXRbeta in NB cells resulted in marked growth inhibition and cell death, which increased after retinoid treatment. However, only proteins from the RXRbeta transfectants exhibited specific RXRbeta binding to the betaRARE in vitro and in vivo, enhanced histone acetylation and increased endogenous RARbeta expression.

Fig1. RXRβ binds the βRARE in retinoid-treated NB cells.

Fig2. Transactivation of the βRARE by RXRs in NB cells.

Case Study 2: Hong Guo, 2023

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are life-threatening conditions with excessive inflammation in the lung. Glucocorticoids had been widely used for ALI/ARDS, but their clinical benefit remains unclear. Here, the researchers tackled the problem by conjugating prednisolone (PSL) with a targeting peptide termed CRV. Systemically administered CRV selectively homes to the inflamed lung of a murine ALI model, but not healthy organs or the lung of healthy mice. The expression of the CRV receptor, retinoid X receptor β, was elevated in the lung of ALI mice and patients with interstitial lung diseases, which may be the basis of CRV targeting. They then covalently conjugated PSL and CRV with a reactive oxygen species (ROS)-responsive linker in the middle. While being intact in blood, the ROS linker was cleaved intracellularly to release PSL for action. In vitro, CRV-PSL showed an anti-inflammatory effect similar to that of PSL. In vivo, CRV conjugation increased the amount of PSL in the inflamed lung but reduced its accumulation in healthy organs. Accordingly, CRV-PSL significantly reduced lung injury and immune-related side effects elsewhere.

Fig3. Representative immunohistochemistry (IHC) images of targeting RXRB by CRV peptide in the lung of ALI mice.

Fig4. Representative immunofluorescence (IF) images of colocalization of rabbit anti-RXRB antibody with CD11b in PBS controls (top) and acute lung injury (ALI) mice (bottom).

RXRB has several biochemical functions, for example, 9-cis retinoic acid receptor activity,RNA polymerase II distal enhancer sequence-specific DNA binding,RNA polymerase II regulatory region sequence-specific DNA binding. Some of the functions are cooperated with other proteins, some of the functions could acted by RXRB itself. We selected most functions RXRB had, and list some proteins which have the same functions with RXRB. You can find most of the proteins on our site.

RXRB has direct interactions with proteins and molecules. Those interactions were detected by several methods such as yeast two hybrid, co-IP, pull-down and so on. We selected proteins and molecules interacted with RXRB here. Most of them are supplied by our site. Hope this information will be useful for your research of RXRB.

RARA;SPOP;CACNA1B;RUTBC1;CPLX1;NUDT21;TBCA;MBP;SSB;CLTA;HSP90B1;PTMS;PCSK6;VCP