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Comparison of kinetic properties between MSS4 and Rab3 A GRF GDP/GTP exchange proteins
Author(s) -
Miyazaki Akira,
Sasaki Takuya,
Araki Keishi,
Ueno Nozomi,
Imazumi Katsunori,
Nagano Fumiko,
Takahashi Kazuo,
Takai Yoshimi
Publication year - 1994
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(94)00804-3
Subject(s) - rab , gtp' , chemistry , biochemistry , biophysics , gtpase , enzyme , biology
The kinetic properties of MSS4 are studied in comparison with those of Rab 3A GRF. MSS4 stimulates the dissociation of [ 3 H]GDP from the lipid‐modified and lipid‐unmodified forms of Rab 3A to the same extent, although Rab 3A GRF is more effective on the lipid‐modified form than on the lipid‐unmodified form. Both MSS4 and Rab 3A GRF are inactive on other Rab/Sec/Ypt family members including at least Rab 2, Rab 5, and Rab 11. Rab GDI inhibits the MSS4 and Rab 3A GRF effects on the lipid‐modified form of Rab 3A, but the doses of Rab GDI necessary for this inhibitory effect on Rab 3A GRF are lower than those on MSS4. Moreover, Rab GDI slightly inhibits the Rab 3A GRF effect on the lipid‐unmodified form of Rab 3A, but does not affect the MSS4 effect on the lipid‐unmodified form of Rab 3A. These results suggest that MSS4 and Rab 3A GRF are different GDP/GTP exchange proteins for Rab 3A.