title: Small GTPases and their guanine-nucleotide exchange factors and GTPase-activating proteins in neutrophil recruitment.
abstract: OBJECTIVE
  The review describes the roles of Rho- and Rap-guanosine triphosphatases (GTPases) and of their activators, guanine-nucleotide exchange factors (GEFs), and inhibitors, GTPase activating proteins (GAPs), in neutrophil recruitment from the blood stream into inflamed tissues, with a focus on recently identified roles in neutrophils, endothelial cells, and platelets.
  
  
  RESULTS
  Recent studies have identified important roles of Rho- and Rap-GTPases, and of their GEFs and GAPs, in the neutrophil recruitment cascade. These proteins control the upregulation and/or activation of adhesion molecules on the surface of neutrophils, endothelial cells, and platelets, and they alter cell/cell adhesion in the vascular endothelium. This enables the capture of neutrophils from the blood stream, their migration along and through the vessel wall, and their passage into the inflamed tissue. In particular, it has recently become clear that P-Rex and Vav family Rac-GEFs in platelets are crucial for neutrophil recruitment.
  
  
  CONCLUSIONS
  These recent findings have contributed greatly to our understanding of the signalling pathways that control neutrophil recruitment to sites of inflammation and have opened up new avenues of research in this field.
authors.affiliation: Signalling Programme, Babraham Institute, Cambridge, UK.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Baker
authors.forename: Dingxin
authors.initials: D
authors.lastname: Pan
authors.forename: Heidi C E
authors.initials: HC
authors.lastname: Welch
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D006801:Humans; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism*; D020556:Neutrophil Infiltration / Q000502:physiology*; D009504:Neutrophils / Q000502:physiology*; D011485:Protein Binding; D015398:Signal Transduction; D020668:rap GTP-Binding Proteins / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000378:metabolism
chemical_list: D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D020559:Monomeric GTP-Binding Proteins; D020668:rap GTP-Binding Proteins; D020741:rho GTP-Binding Proteins