title: Role of SNTA1 in Rac1 activation, modulation of ROS generation, and migratory potential of human breast cancer cells.
abstract: BACKGROUND
  Alpha-1-syntrophin (SNTA1) has been implicated in the activation of Rac1. However, the underlying mechanism has not yet been explored. Here, we show that a novel complex, involving SNTA1, P66shc, and Grb2 proteins, is involved in Rac1 activation.
  
  
  METHODS
  Co-immunoprecipitation assays were used to show the complex formation, while siRNAs and shRNAs were used to downregulate expression of these proteins. Various Rac1 activation assays and functional assays, such as migration assays, in vitro wound healing assays, cell proliferation assays, and ROS generation assays, were also performed.
  
  
  RESULTS
  The results showed a significant increase in activation of Rac1 when SNTA1 and P66shc were overexpressed, whereas depletion of SNTA1 and P66shc expression effectively reduced the levels of active Rac1. The results indicated a significant displacement of Sos1 protein from Grb2 when SNTA1 and P66shc are overexpressed in breast cancer cell lines, resulting in Sos1 predominantly forming a complex with Eps8 and E3b1. In addition, the SNTA1/P66shc-mediated Rac1 activation resulted in an increase in reactive oxygen species (ROS) production and migratory potential in human breast cancer cells.
  
  
  CONCLUSIONS
  Together, our results present a possible mechanism of Rac1 activation involving SNTA1 and emphasise its role in ROS generation, cell migration, and acquisition of malignancy.
authors.affiliation: Department of Biotechnology, University of Kashmir, Jammu and Kashmir, India.
authors.forename: H F
authors.initials: HF
authors.lastname: Bhat
authors.affiliation: Department of Biotechnology, University of Kashmir, Jammu and Kashmir, India.
authors.forename: R A
authors.initials: RA
authors.lastname: Baba
authors.affiliation: Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Adams
authors.affiliation: Department of Biotechnology, University of Kashmir, Jammu and Kashmir, India.
authors.forename: F A
authors.initials: FA
authors.lastname: Khanday
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002135:Calcium-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D002465:Cell Movement / Q000235:genetics*; D049109:Cell Proliferation; D005260:Female; D051380:GRB2 Adaptor Protein / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D047468:Immunoprecipitation; D061986:MCF-7 Cells; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics*; D009124:Muscle Proteins / Q000096:biosynthesis / Q000235:genetics*; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins / Q000235:genetics; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D020830:rac1 GTP-Binding Protein / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D002135:Calcium-Binding Proteins; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D008565:Membrane Proteins; D009124:Muscle Proteins; C107953:RAC1 protein, human; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; C091825:syntrophin alpha1; D020830:rac1 GTP-Binding Protein