PPP2R1B

Serine/threonine-protein phosphatase 2A 65 kDa regulatory subunit A beta isoform is an enzyme that in humans is encoded by the PPP2R1B gene.^[5][6][7]

PPP2R1B
Identifiers
Aliases	PPP2R1B, PP2A-Abeta, PR65B, protein phosphatase 2 scaffold subunit Abeta
External IDs	OMIM: 603113; MGI: 1920949; HomoloGene: 70244; GeneCards: PPP2R1B; OMA:PPP2R1B - orthologs
Gene location (Human) Chr. Chromosome 11 (human)[1] Band 11q23.1 Start 111,726,908 bp[1] End 111,766,389 bp[1]
Gene location (Mouse) Chr. Chromosome 9 (mouse)[2] Band 9|9 A5.3 Start 50,756,601 bp[2] End 50,805,529 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in sperm right lobe of liver left testis right testis adipose tissue body of pancreas islet of Langerhans secondary oocyte abdominal fat subcutaneous adipose tissue Top expressed in primitive streak hair follicle fetal liver hematopoietic progenitor cell ureter seminal vesicula white adipose tissue spermatid condyle epithelium of stomach endothelial cell of lymphatic vessel More reference expression data BioGPS More reference expression data
Gene ontology Molecular function protein binding protein serine/threonine phosphatase activity protein phosphatase regulator activity Cellular component membrane raft extracellular exosome protein phosphatase type 2A complex cytoplasm Biological process apoptotic process involved in morphogenesis positive regulation of extrinsic apoptotic signaling pathway in absence of ligand protein dephosphorylation regulation of phosphoprotein phosphatase activity Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 5519 73699 Ensembl ENSG00000137713 ENSMUSG00000032058 UniProt P30154 Q7TNP2 RefSeq (mRNA) NM_001177562 NM_001177563 NM_002716 NM_181699 NM_181700 NM_001034085 NM_001286553 NM_028614 RefSeq (protein) NP_001171033 NP_001171034 NP_002707 NP_859050 NP_859051 NP_001029257 NP_001273482 NP_082890 Location (UCSC) Chr 11: 111.73 – 111.77 Mb Chr 9: 50.76 – 50.81 Mb PubMed search [3] [4]
Wikidata
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Function

This gene encodes a constant regulatory subunit of protein phosphatase 2. Protein phosphatase 2 is one of the four major Ser/Thr phosphatases, and it is implicated in the negative control of cell growth and division. It consists of a common heteromeric core enzyme, which is composed of a catalytic subunit and a constant regulatory subunit, that associates with a variety of regulatory subunits. The constant regulatory subunit A serves as a scaffolding molecule to coordinate the assembly of the catalytic subunit and a variable regulatory B subunit. This gene encodes a beta isoform of the constant regulatory subunit A. Defects in this gene could be the cause of some lung and colon cancers. At least two transcript variants encoding different isoforms have been found for this gene.^[7]

Discovery

The PPP2R1B gene was discovered as part of the Human Genome Project research center focused on chromosome 11.^[8][9]

Clinical significance

Somatic alterations in PPP2R1B have been identified in colorectal and lung cancer tumors and cell lines,^[8] with evidence that these alterations affect protein function, supporting a role for PPP2R1B as a candidate tumor suppressor gene in these cancers. Experimental studies have shown that suppression of PPP2R1B expression enables immortalized human cells to become tumorigenic, and that the wild-type protein forms a complex with the small GTPase RalA. These findings support the role of PPP2R1B as a tumor suppressor involved in regulating RalA function.^[10]

A case series described nine cancer patients with germline loss-of-function (LOF) variants in PPP2R1B, with breast cancer being the most frequently observed diagnosis.^[11] In all documented cases, individuals also had a family history of cancers including breast, ovarian, prostate, uterine, renal, and colorectal cancer, suggesting that PPP2R1B may function as a predisposition gene in breast and potentially other cancers.^[6]

Interactions

PPP2R1B has been shown to interact with:

• PPP2CA,^[12][13]
• PPP2CB,^[12]
• PPP2R2A,^[12][14]
• PPP2R3B,^[12]
• PPP2R5A,^[12][13][15]
• PPP2R5B,^[15]
• PPP2R5C,^[15]
• PPP2R5D,^[15] and
• PPP2R5E.^[15]