Regulation of Angiotensin II Type 1A Receptor Intracellular Retention, Degradation, and Recycling by Rab5, Rab7, and Rab11 GTPases

Lianne B Dale,Jennifer L Seachrist,Andy V Babwah,Stephen S.G Ferguson

doi:10.1074/jbc.m313333200

Lianne B Dale, Jennifer L Seachrist + Show 2 more

Open Access

https://doi.org/10.1074/jbc.m313333200

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Abstract

Previous studies have demonstrated that the interaction of the angiotensin II type 1A receptor (AT(1A)R) carboxyl-terminal tail with Rab5a may modulate Rab5a activity, leading to the homotypic fusion of endocytic vesicles. Therefore, we have investigated whether AT(1A)R/Rab5a interactions mediate the retention of AT(1A)R.beta-arrestin complexes in early endosomes and whether the overexpression of Rab7 and Rab11 GTPases influences AT(1A)R lysosomal degradation and plasma membrane recycling. We found that internalized AT(1A)R was retained in Rab5a-positive early endosomes and was neither targeted to lysosomes nor recycled back to the cell surface, whereas a mutant defective in Rab5a binding, AT(1A)R-(1-349), was targeted to lysosomes for degradation. However, the loss of Rab5a binding to the AT(1A)R carboxyl-terminal tail did not promote AT(1A)R recycling. Rather, it was the stable binding of beta-arrestin to the AT(1A)R that prevented, at least in part, AT(1A)R recycling. The overexpression of wild-type Rab7 and Rab7-Q67L resulted in both increased AT(1A)R degradation and AT(1A)R targeting to lysosomes. The Rab7 expression-dependent transition of "putative" AT(1A)R.beta-arrestin complexes to late endosomes was blocked by the expression of dominant-negative Rab5a-S34N. Rab11 overexpression established AT(1A)R recycling and promoted the redistribution of AT(1A)R.beta-arrestin complexes from early to recycling endosomes. Taken together, our data suggest that Rab5, Rab7, and Rab11 work in concert with one another to regulate the intracellular trafficking patterns of the AT(1A)R.

Highlights

Previous studies have demonstrated that the interaction of the angiotensin II type 1A receptor (AT1AR) carboxyl-terminal tail with Rab5a may modulate Rab5a activity, leading to the homotypic fusion of endocytic vesicles
We have investigated whether AT1AR/Rab5a interactions mediate the retention of AT1AR1⁄7␤-arrestin complexes in early endosomes and whether the overexpression of Rab7 and Rab11 GTPases influences AT1AR lysosomal degradation and plasma membrane recycling
In response to a 3-h treatment of the same HEK 293 cell with 100 nM angiotensin II (AngII), AT1AR1⁄7␤-arrestin-2-GFP complexes internalized to large hollow core endosomal structures (Fig. 1B)

Summary

Introduction

Previous studies have demonstrated that the interaction of the angiotensin II type 1A receptor (AT1AR) carboxyl-terminal tail with Rab5a may modulate Rab5a activity, leading to the homotypic fusion of endocytic vesicles. We have investigated whether AT1AR/Rab5a interactions mediate the retention of AT1AR1⁄7␤-arrestin complexes in early endosomes and whether the overexpression of Rab7 and Rab11 GTPases influences AT1AR lysosomal degradation and plasma membrane recycling. We examine 1) whether the association of Rab5a with the AT1AR carboxyl-terminal tail prevents the lysosomal degradation and/or plasma membrane recycling of the AT1AR and 2) whether the overexpression of Rab11 and Rab7 GTPases promotes AT1AR recycling and trafficking to late endosomes and lysosomes.

Results

Conclusion