Association with endoplasmic reticulum promotes proteasomal degradation of GADD34 protein.
Abstract
Stress-induced endogenous and ectopically expressed GADD34 proteins were present both
in the cytoplasm and in membranes, with their membrane association showing similar
biochemical properties. Deletion of N-terminal sequences in GADD34-GFP proteins highlighted
an amphipathic helix, whose hydrophobic surface, specifically valine 25 and leucine
29, mediated endoplasmic reticulum (ER) localization. Substitution of leucines for
three arginines on the polar surface indicated that the same helix also mediated the
association of GADD34 with mitochondria. Fluorescence protease protection and chemical
modification of cysteines substituted in the membrane-binding domain pointed to a
monotopic insertion of GADD34 into the outer layer of the ER membrane. Fluorescence
recovery after photobleaching showed that ER association retards the mobility of GADD34
in living cells. Both WT GADD34 and the mutant, V25R, effectively scaffolded the α-isoform
of protein phosphatase-1 (PP1α) and enabled eIF2α dephosphorylation. However, the
largely cytosolic V25R protein displayed a reduced rate of proteasomal degradation,
and unlike WT GADD34, whose ectopic expression resulted in a dilated or distended
ER, V25R did not modify ER morphology. These studies suggested that the association
of with ER modulates intracellular trafficking and proteasomal degradation of GADD34,
and in turn, its ability to modify ER morphology.
Type
Journal articleSubject
COS CellsHela Cells
Cytoplasm
Endoplasmic Reticulum
Cytosol
Animals
Cercopithecus aethiops
Humans
Proteasome Endopeptidase Complex
Arginine
Protein Structure, Tertiary
Protein Binding
Phosphorylation
Mutation
Protein Phosphatase 1
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https://hdl.handle.net/10161/17231Published Version (Please cite this version)
10.1074/jbc.m110.212787Publication Info
Zhou, Wei; Brush, Matthew H; Choy, Meng S; & Shenolikar, Shirish (2011). Association with endoplasmic reticulum promotes proteasomal degradation of GADD34
protein. The Journal of biological chemistry, 286(24). pp. 21687-21696. 10.1074/jbc.m110.212787. Retrieved from https://hdl.handle.net/10161/17231.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Shirish Shenolikar
Professor Emeritus of Psychiatry and Behavioral Sciences
Protein phosphorylation controls a wide range of physiological processes in mammalian
tissues. Phosphorylation state of cellular proteins is controlled by the opposing
actions of protein kinases and phosphatases that are regulated by hormones, neurotransmitters,
growth factors and other environmental cues. Our research attempts to understand the
communication between protein kinases and phosphatases that dictates cellular protein
phosphorylation and the cell's response to hormones. Over the

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