title: Regulation of actin dynamics in pollen tubes: control of actin polymer level.
abstract: Actin cytoskeleton undergoes rapid reorganization in response to internal and external cues. How the dynamics of actin cytoskeleton are regulated, and how its dynamics relate to its function are fundamental questions in plant cell biology. The pollen tube is a well characterized actin-based cell morphogenesis in plants. One of the striking features of actin cytoskeleton characterized in the pollen tube is its surprisingly low level of actin polymer. This special phenomenon might relate to the function of actin cytoskeleton in pollen tubes. Understanding the molecular mechanism underlying this special phenomenon requires careful analysis of actin-binding proteins that modulate actin dynamics directly. Recent biochemical and biophysical analyses of several highly conserved plant actin-binding proteins reveal unusual and unexpected properties, which emphasizes the importance of carefully analyzing their action mechanism and cellular activity. In this review, we highlight an actin monomer sequestering protein, a barbed end capping protein and an F-actin severing and dynamizing protein in plant. We propose that these proteins function in harmony to regulate actin dynamics and maintain the low level of actin polymer in pollen tubes.
authors.affiliation: Center for Signal Transduction and Metabolomics, Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
authors.forename: Naizhi
authors.initials: N
authors.lastname: Chen
authors.forename: Xiaolu
authors.initials: X
authors.lastname: Qu
authors.forename: Youjun
authors.initials: Y
authors.lastname: Wu
authors.forename: Shanjin
authors.initials: S
authors.lastname: Huang
mesh_terms: D051344:Actin Capping Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D000199:Actins / Q000378:metabolism*; D008840:Microfilament Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D008954:Models, Biological; D008958:Models, Molecular; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D053205:Pollen Tube / Q000378:metabolism*
chemical_list: D051344:Actin Capping Proteins; D000199:Actins; D008840:Microfilament Proteins; D010940:Plant Proteins