nBAF complex

Definition

Target type: cellularcomponent

A SWI/SNF-type complex that is found in post-mitotic neurons, and in human contains actin and proteins encoded by the ARID1A/BAF250A or ARID1B/BAF250B, SMARCD1/BAF60A, SMARCD3/BAF60C, SMARCA2/BRM/BAF190B, SMARCA4/BRG1/BAF190A, SMARCB1/BAF47, SMARCC1/BAF155, SMARCE1/BAF57, SMARCC2/BAF170, DPF1/BAF45B, DPF3/BAF45C, ACTL6B/BAF53B genes. The nBAF complex along with CREST plays a role regulating the activity of genes essential for dendrite growth. [GOC:mah, GOC:ss, PMID:17640523]

The nBAF complex, a member of the SWI/SNF family of ATP-dependent chromatin remodelers, plays a crucial role in regulating gene expression. It is a large, multi-subunit complex that exhibits remarkable versatility, capable of altering nucleosome positioning, facilitating DNA accessibility, and influencing the recruitment of transcription factors.

The nBAF complex is characterized by its dynamic composition, assembling from a core set of subunits and incorporating additional components to adapt to specific cellular contexts and developmental stages. The core subunits include:

**1. The ATPase subunit:** This subunit, typically represented by BRG1 or SMARCA4, is responsible for harnessing the energy from ATP hydrolysis to drive the remodeling process. It interacts with DNA and nucleosomes, facilitating their repositioning and altering chromatin structure.

**2. The Snf5 subunit:** This subunit is essential for the stability of the complex and serves as a scaffold for the assembly of other subunits. It binds to the ATPase subunit and interacts with other core components.

**3. The BAF155/ARID1A subunit:** This subunit, also known as ARID1A, is involved in recognizing specific DNA sequences and mediating the interaction of the complex with target genes. It contributes to the recruitment of the nBAF complex to specific genomic regions.

**4. The BAF170/ARID1B subunit:** This subunit, known as ARID1B, exhibits similar functions to BAF155/ARID1A and also contributes to DNA binding specificity. However, it displays distinct expression patterns and regulatory roles.

**5. The BAF47/SMARCB1 subunit:** This subunit is essential for the complex's ability to remodel nucleosomes and is often associated with the recruitment of histone-modifying enzymes.

**6. The BAF57/SMARCD1 subunit:** This subunit contributes to the stability of the complex and participates in the interaction with other subunits.

**7. The BAF60a/SS18 subunit:** This subunit plays a role in the recruitment of the complex to specific promoters and interacts with transcription factors.

**8. The BAF60b/SS18L1 subunit:** This subunit exhibits similar roles to BAF60a and contributes to the complex's versatility in responding to different regulatory signals.

**9. The BAF60c/SS18L2 subunit:** This subunit, along with BAF60a and BAF60b, participates in the recruitment and regulation of specific target genes.

**10. The BAF250a/SMARCA2 subunit:** This subunit, also known as BRM, can replace BRG1 as the ATPase subunit in certain cellular contexts and contributes to the complex's ability to remodel nucleosomes.

In addition to these core subunits, the nBAF complex incorporates a variety of accessory subunits, often referred to as 'module subunits,' which enhance the complex's adaptability and specificity. These module subunits include:

**1. The ENL subunit:** This subunit participates in the recruitment of the complex to active genes and contributes to the regulation of transcription elongation.

**2. The BAF200/SMARCA5 subunit:** This subunit enhances the complex's ability to remodel nucleosomes and interacts with other subunits.

**3. The BAF130/SMARCD3 subunit:** This subunit is involved in regulating the complex's activity and is often associated with developmental processes.

**4. The PBRM1 subunit:** This subunit is a key component of the nBAF complex and plays a critical role in regulating gene expression.

The nBAF complex, through its intricate assembly and dynamic interactions, plays a crucial role in orchestrating chromatin remodeling and shaping the cellular landscape of gene expression. Its aberrant function has been linked to various diseases, highlighting its significance in maintaining cellular homeostasis and proper development.'
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Proteins (2)

Compounds (2)