title: Intrinsic capability of budding yeast cofilin to promote turnover of tropomyosin-bound actin filaments.
abstract: The ability of actin filaments to function in cell morphogenesis and motility is closely coupled to their dynamic properties. Yeast cells contain two prominent actin structures, cables and patches, both of which are rapidly assembled and disassembled. Although genetic studies have shown that rapid actin turnover in patches and cables depends on cofilin, how cofilin might control cable disassembly remains unclear, because tropomyosin, a component of actin cables, is thought to protect actin filaments against the depolymerizing activity of ADF/cofilin. We have identified cofilin as a yeast tropomyosin (Tpm1) binding protein through Tpm1 affinity column and mass spectrometry. Using a variety of assays, we show that yeast cofilin can efficiently depolymerize and sever yeast actin filaments decorated with either Tpm1 or mouse tropomyosins TM1 and TM4. Our results suggest that yeast cofilin has the intrinsic ability to promote actin cable turnover, and that the severing activity may rely on its ability to bind Tpm1.
authors.affiliation: The Stowers Institute for Medical Research, Kansas City, MO, USA.
authors.forename: Xiaoxue
authors.initials: X
authors.lastname: Fan
authors.forename: Skylar
authors.initials: S
authors.lastname: Martin-Brown
authors.forename: Laurence
authors.initials: L
authors.lastname: Florens
authors.forename: Rong
authors.initials: R
authors.lastname: Li
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D000818:Animals; D051338:Cofilin 1 / Q000378:metabolism*; D051379:Mice; D020033:Protein Isoforms / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D014335:Tropomyosin / Q000378:metabolism*
chemical_list: D051338:Cofilin 1; D020033:Protein Isoforms; D029701:Saccharomyces cerevisiae Proteins; D014335:Tropomyosin