Biochemical and genetic analyses provide insight into the structural and mechanistic properties of actin filament disassembly by the Aip1p cofilin complex in Saccharomyces cerevisiae.
Explication of the Aip1p/cofilin/actin filament complex may lead to a more detailed understanding of the mechanisms by which Aip1p and cofilin collaborate to rapidly disassemble filaments. We further characterized the actin-Aip1p interface through a random mutagenic screen of ACT1, identifying a novel Aip1p interaction site on actin. This finding is consistent with our current ternary complex model and offers insights into how Aip1p may disturb intersubunit contacts within an actin filament. In addition, site-directed mutagenesis aimed at interfering with salt bridge interactions at the predicted Aip1p-cofilin interface revealed hyperactive alleles of cof1 and aip1 that support the ternary complex model and suggest that conformational changes in cofilin structure may be transmitted to actin filaments, causing increased destabilization. Furthermore, these data support an active role for Aip1p in promoting actin filament turnover.
Clark
Michael G
MG
Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York 13210, USA.
Amberg
David C
DC
D008841:Actin Cytoskeleton / Q000378:metabolism*; D001665:Binding Sites; D051338:Cofilin 1 / Q000378:metabolism / Q000502:physiology*; D008840:Microfilament Proteins / Q000378:metabolism / Q000502:physiology*; D046912:Multiprotein Complexes / Q000378:metabolism / Q000502:physiology; D011487:Protein Conformation; D025941:Protein Interaction Mapping; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism / Q000502:physiology
D051338:Cofilin 1; D008840:Microfilament Proteins; D046912:Multiprotein Complexes; D029701:Saccharomyces cerevisiae Proteins; C115237:actin interacting protein 1