title: Accelerated actin filament polymerization from microtubule plus ends.
abstract: Microtubules (MTs) govern actin network remodeling in a wide range of biological processes, yet the mechanisms underlying this cytoskeletal cross-talk have remained obscure. We used single-molecule fluorescence microscopy to show that the MT plus-end-associated protein CLIP-170 binds tightly to formins to accelerate actin filament elongation. Furthermore, we observed mDia1 dimers and CLIP-170 dimers cotracking growing filament ends for several minutes. CLIP-170-mDia1 complexes promoted actin polymerization ~18 times faster than free-barbed-end growth while simultaneously enhancing protection from capping proteins. We used a MT-actin dynamics co-reconstitution system to observe CLIP-170-mDia1 complexes being recruited to growing MT ends by EB1. The complexes triggered rapid growth of actin filaments that remained attached to the MT surface. These activities of CLIP-170 were required in primary neurons for normal dendritic morphology. Thus, our results reveal a cellular mechanism whereby growing MT plus ends direct rapid actin assembly.
authors.affiliation: Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Henty-Ridilla
authors.affiliation: Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA.
authors.forename: Aneliya
authors.initials: A
authors.lastname: Rankova
authors.affiliation: Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA.
authors.forename: Julian A
authors.initials: JA
authors.lastname: Eskin
authors.affiliation: Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA.
authors.forename: Katelyn
authors.initials: K
authors.lastname: Kenny
authors.affiliation: Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA. goode@brandeis.edu.
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Goode
mesh_terms: D008841:Actin Cytoskeleton / Q000737:chemistry* / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000737:chemistry*; D005326:Fetal Proteins / Q000737:chemistry / Q000378:metabolism; D000080865:Formins; D006801:Humans; D008840:Microfilament Proteins / Q000737:chemistry / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000737:chemistry* / Q000378:metabolism; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism; D058105:Polymerization; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization; D051381:Rats
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C108962:DIAPH1 protein, human; D005326:Fetal Proteins; D000080865:Formins; D008840:Microfilament Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; C076744:cytoplasmic linker protein 170