The golgin GMAP-210 is required for efficient membrane trafficking in the early secretory pathway.

Peristera Roboti,Martin Lowe,Keisuke Sato

doi:10.1242/jcs.166710

Abstract

Golgins are coiled-coil proteins that participate in membrane-tethering events at the Golgi complex. Golgin-mediated tethering is thought to be important for vesicular trafficking and Golgi organization. However, the degree to which individual golgins contribute to these processes is poorly defined, and it has been proposed that golgins act in a largely redundant manner. Previous studies on the golgin GMAP-210 (also known as TRIP11), which is mutated in the rare skeletal disorder achondrogenesis type 1A, have yielded conflicting results regarding its involvement in trafficking. Here, we re-investigated the trafficking role of GMAP-210, and found that it is indeed required for efficient trafficking in the secretory pathway. GMAP-210 acts at both the endoplasmic reticulum (ER)-to-Golgi intermediate compartment (ERGIC) and Golgi complex during anterograde trafficking, and is also required for retrograde trafficking to the ER. Using co-depletion experiments, we also found that GMAP-210 acts in a partially redundant manner with the golgin GM130 to ensure efficient anterograde cargo delivery to the cis-Golgi. In summary, our results indicate a role for GMAP-210 in several trafficking steps at the ER–Golgi interface, some of which are partially redundant with another golgin, namely GM130 (also known as GOLGA2).

Highlights

The Golgi complex lies at the heart of the secretory pathway where it acts as a processing factory and sorting hub for cargo proteins and lipids (Rothman, 1981)
Received 27 November 2014; Accepted 16 February 2015 the cytosolic face of the Golgi membrane by their extreme Ctermini (Munro, 2011; Barinaga-Rementeria Ramirez and Lowe, 2009). These features have led to the proposal that golgins extend into the cytoplasm to capture, or tether, transport vesicles to Golgi membranes, which can be followed by membrane fusion in order to facilitate both membrane traffic and assembly or maintenance of Golgi cisternae (Munro, 2011; Barinaga-Rementeria Ramirez and Lowe, 2009)
GMAP-210 is required for efficient endoplasmic reticulum (ER)-to-Golgi trafficking To investigate whether GMAP-210 is required for secretory trafficking, we used the well-characterized model cargo protein ts045-VSVG, a temperature sensitive mutant of the vesicular stomatitis virus glycoprotein

Summary

Introduction

The Golgi complex lies at the heart of the secretory pathway where it acts as a processing factory and sorting hub for cargo proteins and lipids (Rothman, 1981). Received 27 November 2014; Accepted 16 February 2015 the cytosolic face of the Golgi membrane by their extreme Ctermini (Munro, 2011; Barinaga-Rementeria Ramirez and Lowe, 2009). These features have led to the proposal that golgins extend into the cytoplasm to capture, or tether, transport vesicles to Golgi membranes, which can be followed by membrane fusion in order to facilitate both membrane traffic and assembly or maintenance of Golgi cisternae (Munro, 2011; Barinaga-Rementeria Ramirez and Lowe, 2009). Tethering could occur between Golgi membranes to promote stacking or Golgi ribbon formation

Methods

Results

Conclusion