ADP ribosylation factor regulates spectrin binding to the Golgi complex

Proc Natl Acad Sci U S A. 1998 Jul 21;95(15):8607-12. doi: 10.1073/pnas.95.15.8607.

Abstract

Homologues of two major components of the well-characterized erythrocyte plasma-membrane-skeleton, spectrin (a not-yet-cloned isoform, betaI Sigma* spectrin) and ankyrin (AnkG119 and an approximately 195-kDa ankyrin), associate with the Golgi complex. ADP ribosylation factor (ARF) is a small G protein that controls the architecture and dynamics of the Golgi by mechanisms that remain incompletely understood. We find that activated ARF stimulates the in vitro association of betaI Sigma* spectrin with a Golgi fraction, that the Golgi-associated betaI Sigma* spectrin contains epitopes characteristic of the betaI Sigma2 spectrin pleckstrin homology (PH) domain known to bind phosphatidylinositol 4,5-bisphosphate (PtdInsP2), and that ARF recruits betaI Sigma* spectrin by inducing increased PtdInsP2 levels in the Golgi. The stimulation of spectrin binding by ARF is independent of its ability to stimulate phospholipase D or to recruit coat proteins (COP)-I and can be blocked by agents that sequester PtdInsP2. We postulate that a PH domain within betaI Sigma* Golgi spectrin binds PtdInsP2 and acts as a regulated docking site for spectrin on the Golgi. Agents that block the binding of spectrin to the Golgi, either by blocking the PH domain interaction or a constitutive Golgi binding site within spectrin's membrane association domain I, inhibit the transport of vesicular stomatitis virus G protein from endoplasmic reticulum to the medial compartment of the Golgi complex. Collectively, these results suggest that the Golgi-spectrin skeleton plays a central role in regulating the structure and function of this organelle.

Publication types

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

MeSH terms

  • ADP-Ribosylation Factors
  • Animals
  • Ankyrins / metabolism
  • Biological Transport
  • Cell Line
  • Endoplasmic Reticulum / metabolism
  • GTP Phosphohydrolases / metabolism
  • GTP-Binding Proteins / metabolism*
  • Golgi Apparatus / metabolism*
  • Membrane Glycoproteins*
  • Phosphatidylinositol 4,5-Diphosphate / metabolism
  • Protein Binding
  • Rats
  • Spectrin / immunology
  • Spectrin / metabolism*
  • Viral Envelope Proteins / metabolism

Substances

  • Ankyrins
  • G protein, vesicular stomatitis virus
  • Membrane Glycoproteins
  • Phosphatidylinositol 4,5-Diphosphate
  • Viral Envelope Proteins
  • Spectrin
  • GTP Phosphohydrolases
  • GTP-Binding Proteins
  • ADP-Ribosylation Factors