Franco M, Paris S, Chabre M
CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France.
FEBS Lett. 1995 Apr 10;362(3):286-90. doi: 10.1016/0014-5793(95)00258-b.
AlF4- activates heterotrimeric G-proteins G alpha subunits but not small GDP/GTP-binding proteins like ARF1. On retinal membranes containing holotransducin (Gt alpha GDP-Gt beta gamma) and incubated with ARFGDP, AlF4- induced Gt alpha GDP-AlF4 release and ARFGDP binding, probably to the remaining membrane-attached Gt beta gamma. On phospholipid vesicles reconstituted with Gt beta gamma, ARFGDP bound in proportion to Gt beta gamma, and was released upon subsequent Gt alpha GDP addition. Thus ARFGDP competes with Gt alpha GDP for binding to Gt beta gamma, probably through a conserved motif in the 'alpha 2 helix' of Gt alpha and ARF. This motif is found in the C-terminal helix of PH domains that bind to G beta gamma.
AlF4-激活异源三聚体G蛋白的Gα亚基，但不激活像ARF1这样的小GDP/GTP结合蛋白。在含有全转导素（GtαGDP-Gtβγ）并与ARFGDP一起孵育的视网膜膜上，AlF4-诱导GtαGDP-AlF4释放以及ARFGDP结合，可能是与剩余的膜结合Gtβγ结合。在用Gtβγ重构的磷脂囊泡上，ARFGDP与Gtβγ成比例结合，并在随后添加GtαGDP时释放。因此，ARFGDP与GtαGDP竞争与Gtβγ结合，可能是通过Gtα和ARF的“α2螺旋”中的保守基序。该基序存在于与Gβγ结合的PH结构域的C末端螺旋中。
