A GBF1-Dependent Mechanism for Environmentally Responsive Regulation of ER-Golgi Transport

Mafalda Lopes-Da-Silva,Jessica J Mccormack,Jemima J Burden,Kimberly J Harrison-Lavoie,Francesco Ferraro,Daniel F Cutler

doi:10.1016/j.devcel.2019.04.006

Mafalda Lopes-Da-Silva, Jessica J Mccormack + Show 4 more

Open Access

https://doi.org/10.1016/j.devcel.2019.04.006

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Abstract

SummaryHow can anterograde membrane trafficking be modulated by physiological cues? A screen of Golgi-associated proteins revealed that the ARF-GEF GBF1 can selectively modulate the ER-Golgi trafficking of prohaemostatic von Willebrand factor (VWF) and extracellular matrix (ECM) proteins in human endothelial cells and in mouse fibroblasts. The relationship between levels of GBF1 and the trafficking of VWF into forming secretory granules confirmed GBF1 is a limiting factor in this process. Further, GBF1 activation by AMPK couples its control of anterograde trafficking to physiological cues; levels of glucose control GBF1 activation in turn modulating VWF trafficking into secretory granules. GBF1 modulates both ER and TGN exit, the latter dramatically affecting the size of the VWF storage organelles, thereby influencing the hemostatic capacity of the endothelium. The role of AMPK as a central integrating element of cellular pathways with intra- and extra-cellular cues can now be extended to modulation of the anterograde secretory pathway.

Highlights

Effective regulation of demand-driven protein secretion requires the integration of environmental signals with cellular trafficking apparatus
ARF1 can recruit the clathrin Adaptor Protein complex-1 (AP-1) (Zhu et al, 1998, 1999) and phosphoinositide4-kinases (PI4K), which produce phosphoinositide Phosphatidylinositol-4-phosphate (PI4P) (Godi et al, 1999), on Golgi membranes, and we have shown that both AP-1 and PI4K play an important role in Weibel-Palade body (WPB) biogenesis (Lopes da Silva and Cutler, 2016; Lopes da Silva et al, 2016; Lui-Roberts et al, 2005)
We assayed for any effects on WPB biogenesis by measuring the number of WPBs per cell using our unbiased, automated, high throughput-high content morphometric (HTM) analytical methodology (Ferraro et al, 2014), the von Willebrand factor (VWF) content of cells, and their exocytic response to the agonist histamine

Summary

Introduction

Effective regulation of demand-driven protein secretion requires the integration of environmental signals with cellular trafficking apparatus. On the anterograde secretory pathway, the endoplasmic reticulum (ER) and Golgi apparatus are critical cargo processing and sorting stations where multiple signals converge Events at both must be coordinated to effectively deliver fully-functional cargo to the correct post-Golgi destination at appropriate levels. VWF undergoes dimerization in the ER prior to its (Lui-Roberts et al, 2005) transit through the Golgi to the trans-Golgi network (TGN) where protease cleavage, multimerization, and coiling into the proteinaceous tubules that drive the formation of its carrier Weibel-Palade body (WPB) occurs. These WPBs are endothelial-specific secretory organelles that store a variety of factors essential to primary hemostasis and inflammation. Agonist-driven exocytosis of WPBs, which causes the release of very large assemblies of VWF oligomers, is especially important in localized recruitment of platelets to sites of damage and plays a key role in primary hemostasis

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