Helicobacter pylori-induced reactive oxygen species direct turnover of CSN-associated STAMBPL1 and augment apoptotic cell death

Supattra Chaithongyot,Michael Naumann

doi:10.1007/s00018-022-04135-2

Supattra Chaithongyot, Michael Naumann

Open Access

https://doi.org/10.1007/s00018-022-04135-2

Copy DOI

Abstract

Deubiquitinylases (DUBs) are central regulators of the ubiquitin system involved in protein regulation and cell signalling and are important for a variety of physiological processes. Most DUBs are cysteine proteases, and few other proteases are metalloproteases of the JAB1/MPN +/MOV34 protease family (JAMM). STAM-binding protein like 1 (STAMBPL1), a member of the JAMM family, cleaves ubiquitin bonds and has a function in regulating cell survival, Tax-mediated nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation and epithelial-mesenchymal transition. However, the molecular mechanism by which STAMBPL1 influences cell survival is not well defined, especially with regard to its deubiquitinylation function. Here, we show that reactive oxygen species (ROS) induced by chemotherapeutic agents or the human microbial pathogen Helicobacter pylori can induce cullin 1-RING ubiquitin ligase (CRL1) and 26S proteasome-dependent degradation STAMBPL1. Interestingly, STAMBPL1 has a direct interaction with the constitutive photomorphogenic 9 (COP9 or CSN) signalosome subunits CSN5 and CSN6. The interaction with the CSN is required for the stabilisation and function of the STAMBPL1 protein. In addition, STAMBPL1 deubiquitinylates the anti-apoptotic protein Survivin and thus ameliorates cell survival. In summary, our data reveal a previously unknown mechanism by which the deubiquitinylase STAMBPL1 and the E3 ligase CRL1 balance the level of Survivin degradation and thereby determine apoptotic cell death. In response to genotoxic stress, the degradation of STAMBPL1 augments apoptotic cell death. This new mechanism may be useful to develop therapeutic strategies targeting STAMBPL1 in tumours that have high STAMBPL1 and Survivin protein levels.

Highlights

Many signalling molecules and thereby cellular processes are regulated via ubiquitinylation, a reversible protein modification leading to the attachment of the 76-amino acid protein ubiquitin to the ε-amino groups of lysine (K) residues in target proteins, which involves a cascade of three enzymes comprising the ubiquitin-activating enzymes (E1), the ubiquitin conjugation enzymes (E2) and the ubiquitin ligases (E3) [1]
The biggest group of E3 ligases is represented by the Cullin-RING ubiquitin ligases (CRLs), which mark the proteins by K48-ubiquitinylation for subsequent degradation in the ubiquitin-proteasome system (UPS)
Our results showed the accumulation of reactive oxygen species (ROS) after treatment with chemotherapeutic agents or H. pylori infection and a ROS-dependent decline of the STAMBPL1 protein amount (Fig. 2c–e)

Summary

Introduction

Many signalling molecules and thereby cellular processes are regulated via ubiquitinylation, a reversible protein modification leading to the attachment of the 76-amino acid protein ubiquitin to the ε-amino groups of lysine (K) residues in target proteins, which involves a cascade of three enzymes comprising the ubiquitin-activating enzymes (E1), the ubiquitin conjugation enzymes (E2) and the ubiquitin ligases (E3) [1]. CRLs are activated by the covalent modification of the cullin protein with the ubiquitin-like protein neuronal precursor cell-expressed developmentally down-regulated protein 8 (NEDD8). This modification results in a conformational change in the cullin C-terminus that facilitates the ubiquitinylation of substrate proteins [2]. The CSN, an evolutionarily conserved eight-subunit protein complex, negatively regulates CRLs by removing NEDD8 from activated Cullins [3]. Deubiquitinating enzymes (DUBs) oppose the action of the E3 ligases by removing ubiquitin from substrate proteins, resulting in altered protein stability or activity [4]. The human genome codes for approximately 100 DUBs, which are classified into six subclasses based on the structure of their catalytic domains and likely mechanisms of action, namely ubiquitin carboxy-terminal hydrolases (UCHs), ubiquitin-specific proteases (USPs), ovarian tumour proteases (OTUs), Jab1/Pad1/MPN domain-associated metallopeptidases (JAMMs), Machado-Joseph disease protein

Methods

Results

Conclusion