STAM adaptor proteins interact with COPII complexes and function in ER-to-Golgi trafficking

Traffic. 2009 Feb;10(2):201-17. doi: 10.1111/j.1600-0854.2008.00856.x. Epub 2008 Nov 18.

Abstract

Signal-transducing adaptor molecules (STAMs) are involved in growth factor and cytokine signaling as well as receptor degradation, and they form complexes with a number of endocytic proteins, including Hrs and Eps15. In this study, we demonstrate that STAM proteins also localize prominently to early exocytic compartments and profoundly regulate Golgi morphology. Upon STAM overexpression in cells, the Golgi apparatus becomes extensively fragmented and dispersed, but when STAMs are depleted, the Golgi becomes highly condensed. Under both scenarios, vesicular stomatitis virus G protein-green fluorescent protein trafficking to the plasma membrane is markedly inhibited, and recovery of Golgi morphology after Brefeldin A treatment is substantially impaired in STAM-depleted cells. Furthermore, STAM proteins interact with coat protein II (COPII) proteins, probably at endoplasmic reticulum (ER) exit sites, and Sar1 activity is required to maintain the localization of STAMs at discrete sites. Thus, in addition to their roles in signaling and endocytosis, STAMs function prominently in ER-to-Golgi trafficking, most likely through direct interactions with the COPII complex.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • COP-Coated Vesicles / metabolism*
  • COP-Coated Vesicles / ultrastructure
  • Endoplasmic Reticulum / metabolism*
  • Endoplasmic Reticulum / ultrastructure
  • Endosomal Sorting Complexes Required for Transport
  • Exocytosis
  • GTP-Binding Proteins / metabolism
  • Gene Deletion
  • Gene Expression Regulation
  • Golgi Apparatus / metabolism*
  • Golgi Apparatus / ultrastructure
  • HeLa Cells
  • Humans
  • Microscopy, Electron
  • Phenotype
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Protein Binding
  • Protein Transport
  • RNA, Small Interfering / genetics
  • Time Factors
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Endosomal Sorting Complexes Required for Transport
  • Phosphoproteins
  • RNA, Small Interfering
  • STAM protein, human
  • STAM2 protein, human
  • Vesicular Transport Proteins
  • GTP-Binding Proteins