title: [The molecular mechanisms of SM22alpha in cytoskeleton remodeling of vascular smooth muscle cells].
abstract: OBJECTIVE
  To investigate the molecular mechanisms of smooth muscle 22 alpha (SM22alpha) whereby cytoskeleton remodeling of vascular smooth muscle cells (VSMCs) is regulated.
  
  
  METHODS
  Synthetic (dedifferentiated) VSMCs were converted to contractile (differentiated) VSMCs by serum deprivation. Cells were transfected with pEGFP-SM22alpha, and localization of SM22alpha and its relationship with F-actin were observed through fluorescence microscopy. Fractional extraction of proteins and Western blotting were used to detect polymerization of SM alpha-actin in antisense-pcD2-SM22alpha-transfected VSMCs.Furthermore, effect of SM22alpha on F-actin cross-linking was observed by F-actin polymerization experiment.
  
  
  RESULTS
  Fluorescence microscopy showed that SM22alpha co-localized with F-actin in contractile VSMCs. Western blotting of protein extracts from F-/G-actin fractions revealed that polymerization of SM alpha-actin was lower in antisense-pcD2-SM22alpha-transfected VSMCs, in which SM alpha-actin mostly existed as soluble G-actin. Moreover, F-actin polymerization in vitro also showed that GST-SM22alpha could promote cross-linking of F-actin to form thick and bundled stress fibres,while extracts from VSMCs transfected with antisense-pcD2-SM22alpha could not effectively induce the polymerization of F-actin.
  
  
  CONCLUSIONS
  SM22alpha acts as a modulator to participate in VSMC cytoskeleton remodeling. It can not only induce polymerization of G-actin to F-actin, but also promote cross-linking of F-actin to bundled stress fibres, indicating its vital role in cytoskeleton remodeling.
authors.affiliation: Hebei Laboratory of Medical Biotechnology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang 050017, China. wjk@hebmu.edu.cn
authors.forename: Jin-kun
authors.initials: JK
authors.lastname: Wen
authors.forename: Jian-hong
authors.initials: JH
authors.lastname: Shi
authors.forename: Bin
authors.initials: B
authors.lastname: Zheng
authors.forename: Fang
authors.initials: F
authors.lastname: Meng
authors.forename: Mei
authors.initials: M
authors.lastname: Han
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D003599:Cytoskeleton / Q000378:metabolism*; D008297:Male; D008840:Microfilament Proteins / Q000378:metabolism*; D009124:Muscle Proteins / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000199:Actins; D008840:Microfilament Proteins; D009124:Muscle Proteins; C051615:transgelin