Retinoblastoma protein family (IPR028309)

Short name: RB_fam

Overlapping homologous superfamilies


Family relationships


This entry represents the retinoblastoma protein family, including retinoblastoma-associated protein (RB, also known as pRb, RB, p1051), retinoblastoma-like protein 1 (RBL1, also known as p107) and retinoblastoma-like protein 2 (RBL2, also known as RB2 or p130). Members of this family contain a conserved domain named the 'pocket' that interacts with the LXCXE motif found in viral proteins, such as SV40 large T antigen [PMID: 17854503]. Therefore, this family is also called the pocket protein family.

In humans, RB is a tumour suppressor linked to several major cancers [PMID: 6320372]. RB forms complexes with E2Fs and represses gene expression by recruiting chromatin remodeling factors, such as histone deacetylases (HDACs) to E2F-responsive promoters [PMID: 12204530, PMID: 11018009]. This interaction regulates genes necessary for DNA replication and cell cycle. Phosphorylation of RB family by CDK and cyclin complexes leads to release of the repressor complex and enables E2F-dependent gene expression [PMID: 11018009]. Apart from E2Fs, RB also interacts with other transcription factors that govern cell differentiation [PMID: 10630640, PMID: 11545733].

RBL1 and RBL2 are the components of the DREAM complex, which represses cell cycle-dependent genes in quiescent cells and plays a role in the cell cycle-dependent activation of G2/M genes [PMID: 17531812, PMID: 17671431].

GO terms

Biological Process

GO:0051726 regulation of cell cycle
GO:0006357 regulation of transcription by RNA polymerase II

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.