Phosphatidylinositol-dependent actin filament binding by the SWI/SNF-like BAF chromatin remodeling complex.
Recently, several chromatin remodeling complexes in yeast, Drosophila, and mammals have been shown to contain actin and actin-related proteins (arps). However, the function of actin in these complexes is unclear. Here, we show that the mammalian SWI/SNF-like BAF complex binds to phosphatidylinositol 4,5-bisphosphate (PIP2) micelles and PIP2-containing mixed lipid vesicles, and that PIP2 binding allows the complex to associate with actin pointed ends and branch points. Actin binds to at least two distinct domains in the C terminus of the Brg1 protein, and interaction with only one of these domains is sensitive to PIP2. Based on these findings, we propose a model for PIP2 activation of actin binding by relief of intramolecular capping of actin by Brg1.
Rando
Oliver J
OJ
Department of Developmental Biology, Howard Hughes Medical Institute, Stanford University Medical School, Stanford, CA 94305, USA.
Zhao
Keji
K
Janmey
Paul
P
Crabtree
Gerald R
GR
D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D000595:Amino Acid Sequence; D002843:Chromatin / Q000378:metabolism*; D004265:DNA Helicases; D006367:HeLa Cells; D006801:Humans; D008823:Micelles; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D000199:Actins; D002843:Chromatin; D008823:Micelles; D008840:Microfilament Proteins; D009687:Nuclear Proteins; D019269:Phosphatidylinositol 4,5-Diphosphate; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C084108:SMARCA4 protein, human; D004265:DNA Helicases