title: Actin interacting protein1 and actin depolymerizing factor drive rapid actin dynamics in Physcomitrella patens.
abstract: The remodeling of actin networks is required for a variety of cellular processes in eukaryotes. In plants, several actin binding proteins have been implicated in remodeling cortical actin filaments (F-actin). However, the extent to which these proteins support F-actin dynamics in planta has not been tested. Using reverse genetics, complementation analyses, and cell biological approaches, we assessed the in vivo function of two actin turnover proteins: actin interacting protein1 (AIP1) and actin depolymerizing factor (ADF). We report that AIP1 is a single-copy gene in the moss Physcomitrella patens. AIP1 knockout plants are viable but have reduced expansion of tip-growing cells. AIP1 is diffusely cytosolic and functions in a common genetic pathway with ADF to promote tip growth. Specifically, ADF can partially compensate for loss of AIP1, and AIP1 requires ADF for function. Consistent with a role in actin remodeling, AIP1 knockout lines accumulate F-actin bundles, have fewer dynamic ends, and have reduced severing frequency. Importantly, we demonstrate that AIP1 promotes and ADF is essential for cortical F-actin dynamics.
authors: Biology Department, University of Massachusetts, Amherst, Massachusetts 01003, USA.
authors: Robert C
authors: RC
authors: Augustine
authors: Kelli A
authors: KA
authors: Pattavina
authors: Erkan
authors: E
authors: Tüzel
authors: Luis
authors: L
authors: Vidali
authors: Magdalena
authors: M
authors: Bezanilla
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D051339:Actin Depolymerizing Factors / Q000235:genetics / Q000378:metabolism*; D000199:Actins / Q000378:metabolism*; D001483:Base Sequence; D019068:Bryopsida / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D003600:Cytosol / Q000378:metabolism; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D030821:Plants, Genetically Modified; D018749:RNA, Plant / Q000235:genetics; D059386:Reverse Genetics; D017422:Sequence Analysis, DNA; D013997:Time Factors
chemical_list: D051339:Actin Depolymerizing Factors; D000199:Actins; D018744:DNA, Plant; D008840:Microfilament Proteins; D010940:Plant Proteins; D018749:RNA, Plant; C115237:actin interacting protein 1