Figure 4.

Control of Golgi function by PKA and Src family kinase. A certain sub-population of PKA holoenzyme is localized at the Golgi, where it can be activated by increases in intracellular cAMP. Activated PKA phosphorylates Arf1 and KDEL receptor, which is important for retrograde recycling of ER proteins from the cis-Golgi. KDEL receptor in complex with ER chaperones activates Golgi-localized Src family kinases (Src), which in turn up-regulates intra-Golgi traffic. In addition, activation of Src induces changes in Golgi structure and induces vesiculation during secretion. PKA is also involved in regulating Golgi structure but the specific targets in this mechanism are unknown.