ATP-Dependent protease LonA from E. coli (Ec-Lon), belonging to the superfamily of AAA+ proteins, is a key member of the protein quality control system in bacterial cells. Ec-Lon functions as homohexamer and degrades abnormal and defective polypeptides as well as a number of regulatory proteins by the processive mechanism. Ec-Lon subunit includes--the both ATPase and proteolytic components (AAA+ module and P domain) in addition to the unique non-catalytic region formed by the N-terminal (N) and the inserted c-helical (HI(CC)) domains. The mutant forms Lon-R164A, Lon-R192A and Lon-Y294A have been obtained and characterized in order to reveal the role of the HI (CC) domain for the enzyme functioning. C-Terminal part of the HI (CC) domain is shown to display an allosteric effect on the efficiency of the enzyme ATPase and proteolytic sites while its coiled-coil (CC) region is involved in the interaction with the protein substrate.
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http://dx.doi.org/10.1134/s1068162015050076 | DOI Listing |
Proc Natl Acad Sci U S A
February 2025
Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada.
ClpXP is a two-component mitochondrial matrix protease. The caseinolytic mitochondrial matrix peptidase chaperone subunit X (ClpX) recognizes and translocates protein substrates into the degradation chamber of the caseinolytic protease P (ClpP) for proteolysis. ClpXP degrades damaged respiratory chain proteins and is necessary for cancer cell survival.
View Article and Find Full Text PDFSci Adv
January 2025
Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
The stability of RNA polymerase II (Pol II) is tightly regulated during transcriptional elongation for proper control of gene expression. Our recent studies revealed that promoter-proximal Pol II is destabilized via the ubiquitin E3 ligase cullin 3 (CUL3) upon loss of transcription elongation factor SPT5. Here, we investigate how CUL3 recognizes chromatin-bound Pol II as a substrate.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115.
Epstein-Barr virus (EBV) establishes persistent infection, causes infectious mononucleosis, is a major trigger for multiple sclerosis and contributes to multiple cancers. Yet, knowledge remains incomplete about how the virus remodels host B cells to support lytic replication. We previously identified that EBV lytic replication results in selective depletion of plasma membrane (PM) B cell receptor (BCR) complexes, composed of immunoglobulin and the CD79A and CD79B signaling chains.
View Article and Find Full Text PDFDiscov Oncol
January 2025
Binzhou Medical University School of Nursing, Binzhou, 256603, Shandong, China.
Purpose: RING Finger 187 (RNF187) has recently emerged as a potential contributor to tumorigenesis. However, a comprehensive pan-cancer analysis of RNF187 in human tumors has not been undertaken until now.
Methods: Our study aims to investigate RNF187 expression across 33 different types of human tumors, utilizing data from the TCGA and GTEx databases.
Proc Natl Acad Sci U S A
January 2025
Department of Medical Neuroscience, SUSTech Center for Pain Medicine, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China.
Ubiquitin-proteasomal degradation of K/Cl cotransporter 2 (KCC2) in the ventral posteromedial nucleus (VPM) has been demonstrated to serve as a common mechanism by which the brain emerges from anesthesia and regains consciousness. Ubiquitin-proteasomal degradation of KCC2 during anesthesia is driven by E3 ligase Fbxl4. However, the mechanism by which ubiquitinated KCC2 is targeted to the proteasome has not been elucidated.
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