A Naturally Occurring Splice Variant of GGA1 Inhibits the Anterograde Post-Golgi Traffic of \u03b12B-Adrenergic Receptor

Maoxiang Zhang,Chunman Li,Nenggui Xu,Xin Xu,Guangyu Wu,Wei Huang

doi:10.1038/s41598-019-46547-4

Maoxiang Zhang, Chunman Li + Show 4 more

Open Access

PDF Available

https://doi.org/10.1038/s41598-019-46547-4

Copy DOI

Export

Save

Cite

Abstract
Highlights/Summary
Full-Text PDF
Similar Papers

Abstract

Listen

The regulatory mechanisms of cell surface targeting of nascent G protein-coupled receptors (GPCRs) en route from the endoplasmic reticulum through the Golgi remain poorly understood. We have recently demonstrated that three Golgi-localized, γ-adaptin ear domain homology, ADP ribosylation factor-binding proteins (GGAs) mediate the post-Golgi export of α2B-adrenergic receptor (α2B-AR), a prototypic GPCR, and directly interact with the receptor. In particular, GGA1 interaction with α2B-AR is mediated via its hinge domain. Here we determined the role of a naturally occurring truncated form of GGA1 (GGA1t) which lacks the N-terminal portion of the hinge domain in α2B-AR trafficking and elucidated the underlying mechanisms. We demonstrated that both GGA1 and GGA1t were colocalized and mainly expressed at the Golgi. In marked contrast to GGA1, the expression of GGA1t significantly attenuated the cell surface export of newly synthesized α2B-AR from the Golgi and in parallel receptor-mediated signaling. Furthermore, we found that GGA1t formed homodimers and heterodimers with GGA1. More interestingly, GGA1t was unable to bind the cargo α2B-AR and to recruit clathrin onto the trans-Golgi network. These data provide evidence implicating that the truncated form of GGA1 behaviors as a dominant-negative regulator for the cell surface export of α2B-AR and this function of GGA1t is attributed to its abilities to dimerize with its wide type counterpart and to inhibit cargo interaction and clathrin recruitment to form specialized transport vesicles.

Highlights

G protein-coupled receptors (GPCRs) are the most structurally diverse family of signaling proteins and regulate a variety of cell function
As we have demonstrated that three GGAs use different domains to interact with α2B-adrenergic receptor (α2B-AR), among them the GGA1 hinge domain is responsible for the interaction with α2B-AR35,36, in this study we have determined the role of a spliced variant of GGA1 lacking the N-terminal portion of the hinge domain (GGA1t) in the cell surface trafficking of α2B-AR
We have demonstrated that this truncated GGA1 variant plays a dominant negative role in the export of α2B-AR and its inhibitory function is likely mediated through multiple mechanisms, including dimerization with wild-type counterpart and loss of the abilities to interact with the receptor and to recruit clathrin onto the membrane

Summary

Introduction

G protein-coupled receptors (GPCRs) are the most structurally diverse family of signaling proteins and regulate a variety of cell function. Numerous studies have demonstrated that, by virtue of their ability to directly interact with many other proteins, both the ICL3 and the CT are the most important domains in the receptors that control almost every function the receptors perform, including G protein-coupling, phosphorylation, signal termination and trafficking[5,6,7]. We have demonstrated that this truncated GGA1 variant plays a dominant negative role in the export of α2B-AR and its inhibitory function is likely mediated through multiple mechanisms, including dimerization with wild-type counterpart and loss of the abilities to interact with the receptor and to recruit clathrin onto the membrane

Methods

Results

Conclusion