Aluminium fluoride associates with the small guanine nucleotide binding proteins

Abstract

AlF 4 − has long been known to associate with and activate the GDP-bound alpha subunits of heterotrimeric G-proteins. Recently the small guanine nucleotide binding protein Ras has also been shown to associate with AlF 4 − in the presence of stoichiometric amounts of its G TPase a ctivating p rotein (GAP). Here we present the isolation of a stable Ras·GDP·AlF 4 −·GAP ternary complex by gel filtration. In addition, we generalise the association of AlF 4 − with the small GTP-binding proteins by demonstrating ternary complex formation for the Cdc42, Rap and Ran proteins in the presence of their respective GAP proteins.