Small GTP-binding proteins of the ADP-ribosylation fac-tor （Arf） family control various cell functional responses including protein transport and recycling between different cellular compartments, phagocytosis, prol...Small GTP-binding proteins of the ADP-ribosylation fac-tor （Arf） family control various cell functional responses including protein transport and recycling between different cellular compartments, phagocytosis, prolif-eration, cytoskeletal remodelling, and migration. The activity of Arfs is tightly regulated. GTPase-activating proteins （GAPs） inactivate Arfs by stimulating GTP hydrolysis, and guanine nucleotide exchange factors （GEFs） stimulate the conversion of inactive GDP-bound Arf to the active GTP-bound conformation. There is increasing evidence that Arf small GTPases contribute to cancer growth and invasion. Increased expression of Arf6 and of Arf-GEPs, or deregulation Arf-GAP functions have been correlated with enhanced invasive capacity of tumor cells and metastasis. The spatiotemporal spe-cifcity of Arf activation is dictated by their GEFs that integrate various signals in stimulated cells. Brefeldin A （BFA）, which inactivates a subset of Arf-GEFs, has been very useful for assessing the function of Golgi-localized Arfs. However, specifc inhibitors to investigate the individual function of BFA-sensitive and insensitive Arf-GEFs are lacking. In recent years, specifc screens have been developed, and new inhibitors with improved se-lectivity and potency to study cell functional responses regulated by BFA-sensitive and BFA-insensitive Arf pathways have been identified. These inhibitors have been instrumental for our understanding of the spa-tiotemporal activation of Arf proteins in cells and dem-onstrate the feasibility of developing small molecules interfering with Arf activation to prevent tumor invasion and metastasis.展开更多
基金Supported by A Grant from the Canadian Institutes of Health Research(MOP-14790)to Bourgoin SG
文摘Small GTP-binding proteins of the ADP-ribosylation fac-tor （Arf） family control various cell functional responses including protein transport and recycling between different cellular compartments, phagocytosis, prolif-eration, cytoskeletal remodelling, and migration. The activity of Arfs is tightly regulated. GTPase-activating proteins （GAPs） inactivate Arfs by stimulating GTP hydrolysis, and guanine nucleotide exchange factors （GEFs） stimulate the conversion of inactive GDP-bound Arf to the active GTP-bound conformation. There is increasing evidence that Arf small GTPases contribute to cancer growth and invasion. Increased expression of Arf6 and of Arf-GEPs, or deregulation Arf-GAP functions have been correlated with enhanced invasive capacity of tumor cells and metastasis. The spatiotemporal spe-cifcity of Arf activation is dictated by their GEFs that integrate various signals in stimulated cells. Brefeldin A （BFA）, which inactivates a subset of Arf-GEFs, has been very useful for assessing the function of Golgi-localized Arfs. However, specifc inhibitors to investigate the individual function of BFA-sensitive and insensitive Arf-GEFs are lacking. In recent years, specifc screens have been developed, and new inhibitors with improved se-lectivity and potency to study cell functional responses regulated by BFA-sensitive and BFA-insensitive Arf pathways have been identified. These inhibitors have been instrumental for our understanding of the spa-tiotemporal activation of Arf proteins in cells and dem-onstrate the feasibility of developing small molecules interfering with Arf activation to prevent tumor invasion and metastasis.
