Coupled deglycosylation-ubiquitination cascade in regulating PD-1 degradation by MDM2.
Posttranslational modifications represent a key step in modulating programmed death-1 (PD-1) functions, but the underlying mechanisms remain incompletely defined. Here, we report crosstalk between deglycosylation and ubiquitination in regulating PD-1 stability. We show that the removal of N-linked glycosylation is a prerequisite for efficient PD-1 ubiquitination and degradation. Murine double ... minute 2 (MDM2) is identified as an E3 ligase of deglycosylated PD-1. In addition, the presence of MDM2 facilitates glycosylated PD-1 interaction with glycosidase NGLY1 and promotes subsequent NGLY1-catalyzed PD-1 deglycosylation. Functionally, we demonstrate that the absence of T cell-specific MDM2 accelerates tumor growth by primarily upregulating PD-1. By stimulating the p53-MDM2 axis, interferon-? (IFN-?) reduces PD-1 levels in T cells, which, in turn, exhibit a synergistic effect on tumor suppression by sensitizing anti-PD-1 immunotherapy. Our study reveals that MDM2 directs PD-1 degradation via a deglycosylation-ubiquitination coupled mechanism and sheds light on a promising strategy to boost cancer immunotherapy by targeting the T cell-specific MDM2-PD-1 regulatory axis.
Mesh Terms:
Animals, Humans, Mice, Neoplasms, Proto-Oncogene Proteins c-mdm2, Tumor Suppressor Protein p53, Ubiquitin-Protein Ligases, Ubiquitination
Animals, Humans, Mice, Neoplasms, Proto-Oncogene Proteins c-mdm2, Tumor Suppressor Protein p53, Ubiquitin-Protein Ligases, Ubiquitination
Cell Rep
Date: Jul. 25, 2023
PubMed ID: 37379210
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