S-Space College of Medicine/School of Medicine (의과대학/대학원) Dept. of Biomedical Sciences (대학원 의과학과) Theses (Master's Degree_의과학과)
Interplay of β-arrestins and Nedd4 E3 ligase regulates ubiquitination and trafficking of mGluR7
- 의과대학 의과학과
- Issue Date
- 서울대학교 대학원
- 학위논문 (석사)-- 서울대학교 대학원 : 의과대학 의과학과, 2018. 2. 서영호.
- Metabotropic glutamate receptor 7A belongs to group III of metabotropic glutamate
receptors as a G protein-coupled receptor. GPCRs undergo a number of post-translational
modifications, which regulate receptor trafficking and function. These modifications of
GPCR have been known as important role for mental disorders such as neurodegenerative
β-arrestins are well known as adaptor protein of seven-transmembrane receptors. And
β-arrestins mediate trafficking of many cell-surface receptors. In many previous reports,
it have been revealed that β-arrestins-dependent ubiquitinylation plays a role in protein
turn-over and receptor trafficking. Although mGluR7A can be an attractive drug target
due to the GPCR properties, whether mGluR7A is a target of ubiquitin conjugation has
not been identified yet.
For the first time I investigated whether mGluR7A is ubiquitinylated in HEK293T cells
and Neuronal cultured cells by immunoprecipitation. These experiments show that
mGluR7A is ubiquitinylated by agonist. And also ubiquitinylation of mGluR7A is
happened at C-terminus and Loop2 regions of mGluR7A.
In this study I found that β-arrestin1 binds strongly to mGluR7A but not beta-arrestin2
in HEK293T cells using immunoprecipitation method. And this binding is regulated with
metabotropic glutamate receptor group III specific agonist (L-AP4) dependent manner.
In addition GST-pull down assay results show that β-arrestin1 binds to C-terminus and
Loop2 of mGluR7A. Furthermore E3 ligase, Nedd4 also binds to mGluR7A and betaii
arrestin1. I identified that this triplet-complex-form regulates mGluR7A ubiquitinylation
in HEK293T cells and neuronal cultured cells.
Also my confocal microscopy imaging results represent that surface stability of
mGluR7A is regulated with the forming complex of mGluR7A, beta-arrestin1 and Nedd4
in neuronal cell. So it is reasonable to assume that beta-arrestin1 and Nedd4 interact
with mGluR7A and make a form of multi-complex to regulate mGluR7A ubiquitinylation and cell surface stability.