Binding kinetics of COPI proteins. Recovery, after bleaching the
Golgi pool, of (A,B) ADP ribosylation factor 1 (ARF1) with and
without aluminium fluoride, (C,D) ARF GTPase-activating protein 1
(ARFGAP1) with and without aluminium fluoride, and (E,F)
ε-COP (ε-coat-protein) with and without aluminium fluoride (black
symbols) with best fits (red lines). Whereas in untreated cells the typical
recovery times T for ARF1 and ARFGAP1 were quite similar (A,
TARF1 ≈ 10 s; C, TARFGAP1 ≈ 9
s), COPI showed a markedly slower recovery (E, TCOPI
≈ 20 s). Applying aluminium fluoride approximately doubled the recovery time
for ARF1 (B, T ≈ 20 s), whereas ARFGAP1 showed only a 30%
slower recovery (D, T ≈ 13 s), and coatomer was locked onto
the membrane (F). WT, wild type.