A degradation motif in STAU1 defines a novel family of proteins involved in inflammation

ABSTRACT: Cancer development is regulated by inflammation. Staufen 1 (STAU1) is an RNA-binding protein whose expression level is critical in cancer cells as it is related to cell proliferation or cell death. STAU1 expression levels are downregulated during mitosis due to its degradation by the E3 ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C). In this paper, we map the molecular determinant involved in STAU1 degradation in mitosis to amino acids 38-50 and, by alanine scanning, we shorten the motif to F39PxPxxLxxxxL50 (FPL-motif). Mutation of the FPL-motif prevents STAU1 degradation by APC/C. Interestingly, a search in databases reveals that the FPL-motif is shared by 15 additional proteins most of them being involved in inflammation. We show that one of these proteins, MAP4K1, is indeed degraded via the FPL-motif; however, it is not a target of APC/C. Using proximity labeling with STAU1, we identify TRIM25, an E3-ubiquitin ligase involved in the innate immune response and interferon production, as responsible for STAU1 and MAP4K1 degradation, dependent on the FPL-motif. These results are consistent with previous studies that linked STAU1 to cancer-induced inflammation and identify a novel degradation motif that likely coordinates a novel family of proteins involved in inflammation.

INSTRUMENT(S): LTQ FT

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Epithelial Cell, Cell Culture

SUBMITTER: Eric Bonneil  

LAB HEAD: Luc Desgroseillers

PROVIDER: PXD037703 | Pride | 2023-02-21

REPOSITORIES: Pride