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The small G‐protein ARF1 GDP binds to the G t βγ subunit of transducin, but not to G t α GDP ‐G t βγ
Author(s) -
Franco Michel,
Paris Sonia,
Chabre Marc
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00258-b
Subject(s) - transducin , protein subunit , chemistry , g protein , combinatorics , biology , crystallography , biochemistry , mathematics , gene , signal transduction
AlF 4 − activates heterotrimeric G‐proteins Gα subunits but not small GDP/GTP‐binding proteins like ARF1. On retinal membranes containing holotransducin (G t α GDP ‐G t βγ and incubated with ARF GDP , AlF 4 − induced G t α GDP‐AlF4 release and ARF GDP binding, probably to the remaining membrane‐attached G t βγ . On phospholipid vesicles reconstitued with G t βγ , ARF GDP bound in proportion to G t βγ , and was released upon subsequent G t α GDP addition. Thus ARF GDP competes with G t α GDP for binding to G t βγ, probably through a conserved motif in the ‘α2 helix’ of G t α and ARF. This motif is found in the C‐terminal helix of PH domains that bind to Gβγ.