Kinetic model of BFA-induced Golgi disassembly in
semi-intact CHO-GT cells. (A) Successive reaction model. In this model,
intact Golgi was transformed to tubular Golgi with the rate constant
k1 and then to fused Golgi with the rate
constant k2. Simple linear first-order
kinetics through a series of three states of Golgi morphology without a
reverse reaction is assumed. Rate constants, obtained from the Golgi
tubule formation and Golgi tubule fusion assays, are shown, and those
obtained from the Golgi disassembly assay are in parentheses. (B)
Concurrent reaction model. In this model, intact Golgi disassembles
through two concurrent pathways. One is the successive pathway
described in A. The other is a direct pathway in which intact Golgi
directly fuses to the ER with the rate constant
k3. Kinetic analysis of the plots from the
Golgi disassembly assay (Figure 9, A and B) was preferentially adapted
to the successive model.