Abstract
Clearance of misfolded proteins by endoplasmic reticulum (ER)-associated degradation (ERAD) requires concerted activity of chaperones, adaptor proteins, ubiquitin ligases, and proteasomes. RNF5 is a ubiquitin ligase anchored to the ER membrane implicated in ERAD via ubiquitination of misfolded proteins. Among RNF5-associated proteins is JNK-associated membrane protein (JAMP), a 7-transmembrane protein located within the ER membrane that facilitates degradation of misfolded proteins through recruitment of proteasomes and ERAD regulatory components. Here we demonstrate that RNF5 associates with JAMP in the ER membrane. This association results in Ubc13-dependent RNF5-mediated noncanonical ubiquitination of JAMP. This ubiquitination does not alter JAMP stability but rather inhibits its association with Rpt5 and p97. Consequently, clearance of misfolded proteins, such as CFTRDelta508 and T cell receptor alpha, is less efficient, resulting in their greater accumulation. Significantly, the RNF5 effect on JAMP is seen prior to and after ER stress response, thereby highlighting a novel mechanism to limit ERAD and proteasome assembly at the ER, to the actual ER stress response.
Publication types
-
Research Support, N.I.H., Extramural
MeSH terms
-
Carrier Proteins / genetics
-
Carrier Proteins / metabolism*
-
Cystic Fibrosis Transmembrane Conductance Regulator / genetics
-
Cystic Fibrosis Transmembrane Conductance Regulator / metabolism
-
DNA-Binding Proteins / genetics
-
DNA-Binding Proteins / metabolism*
-
Endoplasmic Reticulum / genetics
-
Endoplasmic Reticulum / metabolism*
-
HeLa Cells
-
Humans
-
Membrane Glycoproteins / genetics
-
Membrane Glycoproteins / metabolism*
-
Membrane Proteins / genetics
-
Membrane Proteins / metabolism*
-
Proteasome Endopeptidase Complex / genetics
-
Proteasome Endopeptidase Complex / metabolism
-
Protein Folding*
-
Receptors, Antigen, T-Cell, alpha-beta / genetics
-
Receptors, Antigen, T-Cell, alpha-beta / metabolism
-
Stress, Physiological / physiology
-
Ubiquitin-Conjugating Enzymes / genetics
-
Ubiquitin-Conjugating Enzymes / metabolism*
-
Ubiquitin-Protein Ligases
-
Ubiquitination / physiology*
Substances
-
CFTR protein, human
-
Carrier Proteins
-
DNA-Binding Proteins
-
JKAMP protein, human
-
Membrane Glycoproteins
-
Membrane Proteins
-
Receptors, Antigen, T-Cell, alpha-beta
-
Cystic Fibrosis Transmembrane Conductance Regulator
-
UBE2N protein, human
-
Ubiquitin-Conjugating Enzymes
-
RNF5 protein, human
-
Ubiquitin-Protein Ligases
-
Proteasome Endopeptidase Complex