Neurofilaments (NFs), the most abundant cytoskeletal components in large neurons and myelinated axons, are the targets of n-hexane-induced neuropathy, in which a specific loss of NFs protein has been frequently observed. However, the precise mechanisms regulating NFs contents are not well understood. The aim of this study was to elucidate the role of ubiquitin-proteasome system (UPS) in NFs degradation. We first demonstrated that the E3 ligase carboxyl-terminus of Hsc70 interacting protein (CHIP), originally identified as a co-chaperone of Hsc70, directly interacted with NFs medium chain (NF-M) and then enhanced NF-M ubiquitination and degradation after 2,5-hexanedione (HD) treatment. Consistent with this result, the application of proteasome inhibitor MG132 partly reversed HD-induced decrease of NF-M. Finally, we found that other components of UPS system (e.g. ubiquitin-activating enzyme E1, CHIP and proteasome) were significantly increased in sciatic nerve of HD-intoxicated rats. In conclusion, this study indicated that the CHIP ubiquitin ligase complex interacted with and repressed NFs by targeting NFs for ubiquitin-mediated proteolysis, which led to reduction of NFs contents in HD-induced neuropathy.
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http://dx.doi.org/10.1016/j.bcp.2010.12.021 | DOI Listing |
EMBO J
January 2025
Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, 450000, Henan, China.
The carboxyl terminus of Hsc70-interacting protein (CHIP) is pivotal for managing misfolded and aggregated proteins via chaperone networks and degradation pathways. In a preclinical rodent model of CHIP-related ataxia, we observed that CHIP mutations lead to increased levels of phosphodiesterase 9A (PDE9A), whose role in this context remains poorly understood. Here, we investigated the molecular mechanisms underlying the role of PDE9A in CHIP-related ataxia and demonstrated that CHIP binds to PDE9A, facilitating its polyubiquitination and autophagic degradation.
View Article and Find Full Text PDFDiabetes
January 2025
Institute for Developmental and Regenerative Cardiovascular Medicine, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China.
Diabetes is a major risk factor for cardiovascular disease, but the molecular mechanisms underlying diabetic vasculopathy have been elusive. Here we report that inositol hexakisphosphate kinase 1 (IP6K1) mediates hyperglycemia-induced endothelial senescence by rewiring the liver kinase B1 (LKB1) signaling from activating the adenosine monophosphate-activated protein kinase (AMPK) pathway to the p53 pathway. We found that hyperglycemia upregulated IP6K1, which disrupts the Hsp/Hsc70 and carboxyl terminus of Hsc70-interacting protein (CHIP)-mediated LKB1 degradation, leading to increased expression levels of LKB1.
View Article and Find Full Text PDFPNAS Nexus
December 2024
Department of Biological Sciences, National University of Singapore, Singapore 117543.
BCL2/adenovirus E1B 19-kDa protein-interacting protein 2 homolog (BNIP-H or Caytaxin), a pivotal adaptor protein that facilitates cerebellar cortex growth and synaptic transmission, is posttranslationally modified to regulate neuronal function. This study reports the ubiquitination of BNIP-H by Carboxyl terminus of Hsc70-Interacting Protein (CHIP), a U-box containing E3 ligase that is also regulated autoubiquitination. Specifically, it was observed that CHIP autoubiquitinated itself primarily at Lys23 and Lys31 .
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Department of Orthopaedic Surgery, Orthopaedic Research Institute, West China Hospital, West China Medical School, Sichuan University, Chengdu, 610041, China.
Chondrocyte senescence is a key driver of osteoarthritis (OA). Mitochondrial dysfunction and oxidative stress can induce chondrocyte senescence. However, the specific mechanisms by which senescence contributes to OA progression are not fully understood.
View Article and Find Full Text PDFJ Biol Chem
December 2024
The McAllister Heart Institute and Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; The Department of Pathology and Lab Medicine and Computational Medicine Program, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. Electronic address:
Cancer and other chronic diseases are marked by alterations in the protein quality control system, affecting the posttranslational destiny of various proteins that regulate, structure, and catalyze cellular processes. Cellular chaperones, also known as heat shock proteins (HSPs), are pivotal in this system, performing protein triage that often determines the fate of proteins they bind to. Grasping the regulatory mechanisms of HSPs and their associated cofactors is crucial for understanding protein quality control in both healthy and diseased states.
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