A 14-3-3γ dimer-based scaffold bridges CtBP1-S/BARS to PI(4)KIIIβ to regulate post-Golgi carrier for

Abstract

Large pleiomorphic carriers leave the Golgi complex for the plasma membrane by en bloc extrusion of specialized tubular domains, which then undergo fission. Several components of the underlying molecular machinery have been identified, including those involved in the budding/initiation of tubular carrier precursors (for example, the phosphoinositide kinase PI(4)KIIIβ, the GTPase ARF, and FAPP2), and in the fission of these precursors (for example, PKD, CtBP1-S/BARS). However, how these proteins interact to bring about carrier formation is poorly understood. Here, we describe a protein complex that mediates carrier formation and contains budding and fission molecules, as well as other molecules, such as the adaptor protein 14-3-3γ. Specifically, we show that 14-3-3γ dimers bridge CtBP1-S/BARS with PI(4)KIIIβ, and that the resulting complex is stabilized by phosphorylation by PKD and PAK. Disrupting the association of these proteins inhibits the fission of elongating carrier precursors, indicating that this complex couples the carrier budding and fission processes. Formation and fission of large membrane-bound carriers at the Golgi requires coordinated action by a myriad of proteins, including PI(4)KIIIβ and CtBP1-S/BARS. Corda and colleagues reveal that the scaffold protein 14-3-3γ bridges BARS to PI(4)KIIIβ, thus mechanistically linking carrier budding and tubulation with tubule fission.

Cite this article

Valente, C., Turacchio, G., Mariggiò, S. et al. A 14-3-3γ dimer-based scaffold bridges CtBP1-S/BARS to PI(4)KIIIβ to regulate post-Golgi carrier formation. Nat Cell Biol 14, 343–354 (2012). https://doi.org/10.1038/ncb2445

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