title: Fluoroaluminate treatment of rat liver microsomes inhibits GTP-dependent vesicle fusion.
abstract: 1. Inhibition of GTP-dependent membrane fusion of rat liver microsomes requires preincubation of the membranes with GDP (17 microM) and relatively high Mg2+ concentration (0.5 mM) as well as AlCl3 (30 microM) and KF (5 mM). Preincubation is required for maximal inhibition (75%). 2. Vesicle fusion in rat liver microsomes has been demonstrated in the absence of polyethylene glycol (PEG). Further, inhibition by AlF4- of GTP-dependent vesicle fusion in the absence of PEG has been demonstrated. 3. Under similar preincubation conditions AlF4- can bring about inhibition (80%) of the high-affinity PEG-stimulated GTPase activity in rat liver microsomes, previously described by Nicchitta, Joseph & Williamson [(1986) FEBS Lett. 209, 243-248]. 4. Preincubation of small-Mr GTP-binding proteins (Gn proteins) on nitrocellulose strips with GDP (20 pM), AlCl3 (30 microM) and KF (5 mM) results in inhibition of binding of guanosine 5'-[gamma-[35S]thio]triphosphate to Gn proteins. The extent of inhibition of this binding differs for different Gn proteins.
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich, U.K.
authors.forename: J G
authors.initials: JG
authors.lastname: Comerford
authors.forename: A P
authors.initials: AP
authors.lastname: Dawson
mesh_terms: D000535:Aluminum / Q000494:pharmacology*; D017607:Aluminum Compounds; D000818:Animals; D002118:Calcium / Q000378:metabolism; D005459:Fluorides / Q000494:pharmacology*; D020558:GTP Phosphohydrolases / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism*; D008561:Membrane Fusion / Q000187:drug effects*; D008862:Microsomes, Liver / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D011092:Polyethylene Glycols / Q000494:pharmacology; D051381:Rats
chemical_list: D017607:Aluminum Compounds; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D011092:Polyethylene Glycols; D006160:Guanosine Triphosphate; D000535:Aluminum; D020558:GTP Phosphohydrolases; D005459:Fluorides; D002118:Calcium; C032311:aluminum fluoride