SMARCB1 : SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily b, member 1

Description

The SMARCB1 (SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily b, member 1) is a protein-coding gene located on chromosome 22.

The SMARCB1 gene provides instructions for making a protein that forms one piece (subunit) of several different protein groupings called SWI/SNF protein complexes. SWI/SNF complexes regulate gene activity (expression) by a process known as chromatin remodeling. Chromatin is the network of DNA and protein that packages DNA into chromosomes. The structure of chromatin can be changed (remodeled) to alter how tightly DNA is packaged. Chromatin remodeling is one way gene expression is regulated during development; when DNA is tightly packed, gene expression is lower than when DNA is loosely packed. Through their ability to regulate gene activity, SWI/SNF complexes are involved in many processes, including repairing damaged DNA; copying (replicating) DNA; and controlling the growth, division, and maturation (differentiation) of cells. Through these processes, the SMARCB1 protein and other SWI/SNF subunits are thought to act as tumor suppressors, which keep cells from growing and dividing too rapidly or in an uncontrolled way. The role of the SMARCB1 protein within the SWI/SNF complex is not fully understood.

SMARCB1 is a core component of the BAF (hSWI/SNF) complex, an ATP-dependent chromatin-remodeling complex that plays crucial roles in cell proliferation and differentiation, cellular antiviral activities, and tumor suppression. The BAF complex remodels chromatin structure by reducing negative supercoiling, converting nucleosomes into asymmetric structures called altosomes. It stimulates the remodeling activity of SMARCA4/BRG1/BAF190A and is involved in activating the CSF1 promoter. SMARCB1 is part of both the neural progenitor-specific chromatin remodeling complex (npBAF complex) and the neuron-specific chromatin remodeling complex (nBAF complex). During neural development, a switch occurs from a stem/progenitor to a postmitotic chromatin remodeling mechanism as neurons exit the cell cycle. This transition involves a change in subunit composition of the npBAF and nBAF complexes. As neural progenitors differentiate into neurons, npBAF complexes containing ACTL6A/BAF53A and PHF10/BAF45A are replaced by homologous alternative subunits, ACTL6B/BAF53B and DPF1/BAF45B or DPF3/BAF45C, in the neuron-specific nBAF complexes. The npBAF complex is essential for the self-renewal and proliferative capacity of neural stem cells. The nBAF complex, along with CREST, regulates the activity of genes essential for dendrite growth. SMARCB1 plays a key role in cell-cycle control, inducing cell cycle arrest in G0/G1.

SMARCB1 is also known as BAF47, CSS3, INI-1, INI1, MRD15, PPP1R144, RDT, RTPS1, SNF5, SNF5L1, SWNTS1, Sfh1p, Snr1, hSNFS.

Associated Diseases

WES Whole Exome Sequencing

Clinical Exome Sequencing