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In vivo and in vitro Studies of Adaptor-clathrin Interaction
Published on: January 26, 2011
STAM adaptor proteins interact with COPII complexes and function in ER-to-Golgi trafficking
Neggy Rismanchi1, Rosa Puertollano, Craig Blackstone
1Cellular Neurology Unit, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Traffic (Copenhagen, Denmark)
|December 5, 2008
Summary
Signal-transducing adaptor molecules (STAMs) regulate Golgi morphology and ER-to-Golgi trafficking. STAMs interact with COPII proteins, impacting protein transport and cell signaling pathways.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Signal-transducing adaptor molecules (STAMs) are known regulators of growth factor and cytokine signaling pathways.
- STAMs also play a role in receptor degradation and form complexes with endocytic proteins like Hrs and Eps15.
Purpose of the Study:
- To investigate the role of STAMs in cellular trafficking beyond their known functions in signaling and endocytosis.
- To elucidate the impact of STAMs on Golgi morphology and the early secretory pathway.
Main Methods:
- Cellular localization studies of STAM proteins.
- Overexpression and depletion of STAMs in cultured cells.
- Analysis of Golgi apparatus morphology using microscopy.
- Assessment of protein trafficking using viral glycoproteins (VSV G protein-GFP).
- Investigation of STAM interactions with COPII components and Sar1 activity.
Main Results:
- STAM proteins were found to localize to early exocytic compartments.
- STAM manipulation (overexpression or depletion) profoundly altered Golgi morphology, leading to fragmentation or condensation, respectively.
- Trafficking of VSV G protein-GFP to the plasma membrane was inhibited under both STAM overexpression and depletion conditions.
- STAM-depleted cells showed impaired Golgi recovery after Brefeldin A treatment.
- STAMs interact with COPII proteins at ER exit sites, and Sar1 activity is crucial for STAM localization.
Conclusions:
- STAMs play a significant role in ER-to-Golgi trafficking, in addition to their established functions in signaling and endocytosis.
- STAMs likely mediate ER-to-Golgi transport through direct interactions with the COPII complex.
- These findings reveal a novel function for STAMs in the regulation of the early secretory pathway.
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