An alternative splicing variant of E3 ubiquitin ligase ASB2, termed ASB2a, has a distinct N-terminal sequence containing a ubiquitin-interacting motif (UIM) consensus sequence. Examination of the minimal essential region for binding to polyubiquitinated proteins indicated that the UIM consensus sequence (residues 26-41) alone is not enough, and that amino acids 12-41 from the N-terminus of ASB2a is essential for binding. ASB2a(12-41) peptide was chemically synthesized and coupled to Sepharose 4B via disulfide bonds. This ASB2a(12-41) peptide-coupled affinity resin bound both K48- and K63-linked polyubiquitinated proteins in cell lysates and comprehensively captured polyubiquitinated proteins, including polyubiquitinated β-catenin, I-κB, and EGF receptor, which were eluted with 2-mercaptoethanol under non-denaturing conditions. These results indicate that this UIM affinity purification (designated as ubiquitin-trapping) is a useful method to discover polyubiquitinated proteins and their associated proteins.
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http://dx.doi.org/10.1016/j.bbrc.2011.09.022 | DOI Listing |
Autophagy
January 2025
Institute for Experimental Pediatric Hematology and Oncology, Goethe University Frankfurt, Frankfurt am Main, Germany.
Lysosomes are the major cellular organelles responsible for nutrient recycling and degradation of cellular material. Maintenance of lysosomal integrity is essential for cellular homeostasis and lysosomal membrane permeabilization (LMP) sensitizes toward cell death. Damaged lysosomes are repaired or degraded via lysophagy, during which glycans, exposed on ruptured lysosomal membranes, are recognized by galectins leading to K48- and K63-linked poly-ubiquitination (poly-Ub) of lysosomal proteins followed by recruitment of the macroautophagic/autophagic machinery and degradation.
View Article and Find Full Text PDFCirc Res
January 2025
Experimental Research Center, Beijing Institute of Heart, Lung and Blood Vessel Diseases, Beijing Anzhen Hospital, Capital Medical University, China (H.J.).
Background: Metabolic syndrome heightens cardiovascular disease risk primarily through increased arterial stiffness. We previously demonstrated the involvement of YAP (Yes-associated protein) in high-fat/high-sucrose diet (HFHSD)-induced arterial stiffness via modulation of PPM1B (protein phosphatase Mg/Mn-dependent 1B)-lysine63 (K63) deubiquitination. In this study, we aimed to elucidate the role and mechanisms underlying PPM1B deubiquitination in HFHSD-induced arterial stiffness.
View Article and Find Full Text PDFStructure
December 2024
Department of Molecular and Cellular Biology, College of Biological Science, University of Guelph, Guelph, ON, Canada.
The E2/E3 hybrid enzyme UBE2O plays important roles in key biological events, but its autoubiquitination mechanism remains largely unclear. In this study, we determined the crystal structures of full-length (FL) UBE2O from Trametes pubescens (tp) and its ubiquitin-conjugating (UBC) domain. The dimeric FL-tpUBE2O structure revealed interdomain interactions between the conserved regions (CR1-CR2) and UBC.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Department of Biochemistry and Molecular Biology, College of Life Sciences, Shandong Normal University, Jinan, Shandong 250014, China.
Poly(ADP-ribose) polymerase 1 (PARP1) plays a crucial role in DNA repair and genomic stability maintenance. However, the regulatory mechanisms governing PARP1 activity, particularly through deubiquitination, remain poorly elucidated. Using a deubiquitinase (DUB) library binding screen, we identified cylindromatosis (CYLD) as a bona fide DUB for PARP1 in breast cancer cells.
View Article and Find Full Text PDFCell Mol Life Sci
December 2024
Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, China.
Aldosterone-producing adenoma (APA) is a leading cause of primary aldosteronism (PA), a condition marked by excessive aldosterone secretion. CYP11B2, the aldosterone synthase, plays a critical role in aldosterone biosynthesis and the development of APA. Despite its significance, encoding regulatory mechanisms governing CYP11B2, particularly its degradation, remain poorly understood.
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