Arf1 directly recruits the Pik1-Frq1 PI4K complex to regulate the final stages of Golgi maturation

Mol Biol Cell. 2021 May 1;32(10):1064-1080. doi: 10.1091/mbc.E21-02-0069. Epub 2021 Mar 31.

Abstract

Proper Golgi complex function depends on the activity of Arf1, a GTPase whose effectors assemble and transport outgoing vesicles. Phosphatidylinositol 4-phosphate (PI4P) generated at the Golgi by the conserved PI 4-kinase Pik1 (PI4KIIIβ) is also essential for Golgi function, although its precise roles in vesicle formation are less clear. Arf1 has been reported to regulate PI4P production, but whether Pik1 is a direct Arf1 effector is not established. Using a combination of live-cell time-lapse imaging analyses, acute PI4P depletion experiments, and in vitro protein-protein interaction assays on Golgi-mimetic membranes, we present evidence for a model in which Arf1 initiates the final stages of Golgi maturation by tightly controlling PI4P production through direct recruitment of the Pik1-Frq1 PI4-kinase complex. This PI4P serves as a critical signal for AP-1 and secretory vesicle formation, the final events at maturing Golgi compartments. This work therefore establishes the regulatory and temporal context surrounding Golgi PI4P production and its precise roles in Golgi maturation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • 1-Phosphatidylinositol 4-Kinase / physiology
  • Adaptor Proteins, Vesicular Transport / metabolism
  • Calcium-Binding Proteins / physiology
  • Diglycerides / metabolism
  • Golgi Apparatus / physiology*
  • Phosphatidylinositol Phosphates / physiology*
  • Protein Binding
  • Saccharomyces cerevisiae / physiology*
  • Saccharomyces cerevisiae Proteins / physiology*
  • Saccharomycetales
  • Secretory Vesicles / physiology
  • Time-Lapse Imaging

Substances

  • Adaptor Proteins, Vesicular Transport
  • Calcium-Binding Proteins
  • Diglycerides
  • FRQ1 protein, S cerevisiae
  • Phosphatidylinositol Phosphates
  • Saccharomyces cerevisiae Proteins
  • phosphatidylinositol 4-phosphate
  • 1-Phosphatidylinositol 4-Kinase
  • PIK1 protein, S cerevisiae

Supplementary concepts

  • Komagataella pastoris