The multivesicular body (MVB) pathway sorts ubiquitinated membrane cargo to intraluminal vesicles (ILVs) within the endosome, en route to the lysosomal lumen. The pathway involves the sequential action of conserved protein complexes [endosomal sorting complexes required for transport (ESCRTs)], culminating in the activation by ESCRT-II of ESCRT-III, a membrane-sculpting complex. Although this linear pathway of ESCRT activation is widely accepted, a study by Luzio and colleagues in a recent issue of the Biochemical Journal suggests that there is greater complexity in ESCRT-III activation, at least for some MVB cargoes. They show that ubiquitin-dependent sorting of major histocompatibility complex (MHC) class I to the MVB requires the central ESCRT-III complex but does not involve either ESCRT-II or functional links between ESCRT-II and ESCRT-III. Instead, they propose that MHC class I utilizes histidine-domain protein tyrosine phosphatase (HD-PTP), a non-canonical ESCRT interactor, to promote ESCRT-III activation.
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http://dx.doi.org/10.1042/BJ20151115 | DOI Listing |
Clin Transl Med
January 2025
State Key Laboratory of Systems Medicine for Cancer, Shanghai Cancer Institute, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, P.R. China.
Background: Vitamin K-dependent γ-glutamic acid carboxylation (Gla) proteins are calcium-binding and membrane-associated, participating in coagulation, bone turnover, and cancer biology. The molecular function of transmembrane proline-rich Gla proteins (PRRGs) remains unexplored.
Methods: Analysis of pancreatic ductal adenocarcinoma (PDAC) datasets, including transcription profiles, clinical data, and tissue microarrays, was conducted to evaluate PRRG1 expression and its clinical relevance.
Neurotox Res
January 2025
Molecular Neuropsychiatry Section, Intramural Research Program, NIH/ NIDA, 21224, Baltimore, MD, U.S.A.
To identify factors involved in methamphetamine (METH) neurotoxicity, we comprehensively searched for genes which were differentially expressed in mouse striatum after METH administration using differential display (DD) reverse transcription-PCR method and sequent single-strand conformation polymorphism analysis, and found two DD cDNA fragments later identified as mRNA of Nedd4 (neural precursor cell expressed developmentally downregulated 4) WW domain-binding protein 5 (N4WBP5), later named Nedd4 family-interacting protein 1 (Ndfip1). It is an adaptor protein for the binding between Nedd4 of ubiquitin ligase (E3) and target substrate protein for ubiquitination. Northern blot analysis confirmed drastic increases in Ndfip1 mRNA in the striatum after METH injections, and in situ hybridization histochemistry showed that the mRNA expression was increased in the hippocampus and cerebellum at 2 h-2 days, in the cerebral cortex and striatum at 18 h-2 days after single METH administration.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Division of Livestock Infectious Diseases, State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China.
Historically considered to be nonenveloped, hepatitis E virus (HEV), an important zoonotic pathogen, has recently been discovered to egress from infected cells as quasi-enveloped virions. These quasi-enveloped virions circulating in the blood are resistant to neutralizing antibodies, thereby facilitating the stealthy spread of infection. Despite abundant evidence of the essential role of the HEV-encoded ORF3 protein in quasi-enveloped virus formation, the underlying mechanism remains unclear.
View Article and Find Full Text PDFFASEB J
January 2025
State Key Laboratory of Virology, Institute of Medical Virology, Taikang Medical School (School of Basic Medical Sciences), Wuhan University, Wuhan, Hubei, China.
Hantaan virus (HTNV) infection causes severe hemorrhagic fever with renal syndrome (HFRS) in humans and the infectious process can be regulated by autophagy. The phosphatase and tensin homolog (PTEN) protein has antiviral effects and plays a critical role in the autophagy pathway. However, the relationship between PTEN and HTNV infection is not clear and whether PTEN-regulated autophagy involves in HTNV replication is unknown.
View Article and Find Full Text PDFBiochem Biophys Res Commun
February 2025
Department of Ophthalmology, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, China. Electronic address:
Phosphoinositide kinase, FYVE-type zinc finger containing (PIKFYVE) was recently identified as a causative gene for cataract. Pikfyve phosphatidylinositol phosphate kinase domain-deficient (pikfyve) zebrafish lens and PIKFYVE-inhibited human lens epithelial cells developed vacuoles, colocalized with late endosome marker RAB7. In this study, the pikfyvezebrafish with vacuole-like cataract underwent transcriptomic and proteomic analyses to explore the underlying mechanisms of vacuole formation.
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