ACTL6A

This gene encodes a family member of actin-related proteins (ARPs), which share significant amino acid sequence identity to conventional actins. Both actins and ARPs have an actin fold, which is an ATP-binding cleft, as a common feature. The ARPs are involved in diverse cellular processes, including vesicular transport, spindle orientation, nuclear migration and chromatin remodeling. This gene encodes a 53 kDa subunit protein of the BAF (BRG1/brm-associated factor) complex in mammals, which is functionally related to SWI/SNF complex in S. cerevisiae and Drosophila; the latter is thought to facilitate transcriptional activation of specific genes by antagonizing chromatin-mediated transcriptional repression. Together with beta-actin, it is required for maximal ATPase activity of BRG1, and for the association of the BAF complex with chromatin/matrix. Three transcript variants that encode two different protein isoforms have been described.^[7]

ACTL6A is amplified in head and squamous cancers and confers poor prognosis in patients. This is also the first report of amplification of an epigenetic factor by Saladi SV.^[8] In hepatocellular carcinomas, it promotes metastasis.^[9]

ACTL6A has been shown to interact with SMARCA2,^[10][11][12] Myc,^[11] Transformation/transcription domain-associated protein,^[11] RuvB-like 1^[11] and SMARCA4.^[5][10]