Ubiquitin (denoted Ub) receptor proteins as a group must contain a diverse set of binding specificities to distinguish the many forms of polyubiquitin (polyUb) signals. Previous studies suggested that the large class of ubiquitin-associated (UBA) domains contains members with intrinsic specificity for Lys63-linked polyUb or Lys48-linked polyUb, thus explaining how UBA-containing proteins can mediate diverse signaling events. Here we show that previously observed Lys63-polyUb selectivity in UBA domains is the result of an artifact in which the dimeric fusion partner, glutathione S-transferase (GST), positions two UBAs for higher affinity, avid interactions with Lys63-polyUb, but not with Lys48-polyUb. Freed from GST, these UBAs are either nonselective or prefer Lys48-polyUb. Accordingly, NMR experiments reveal no Lys63-polyUb-specific binding epitopes for these UBAs. We reexamine previous conclusions based on GST-UBAs and present an alternative model for how UBAs achieve a diverse range of linkage specificities.
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http://dx.doi.org/10.1038/nsmb.1637 | DOI Listing |
Exp Mol Med
January 2025
Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA, 02115, USA.
In response to extra- and intracellular stimuli that constantly challenge and disturb the proteome, cells rapidly change their proteolytic capacity to maintain proteostasis. Failure of such efforts often becomes a major cause of diseases or is associated with exacerbation. Increase in protein breakdown occurs at multiple steps in the ubiquitin-proteasome system, and the regulation of ubiquitination has been extensively studied.
View Article and Find Full Text PDFChaos
January 2025
CNRS-IRD-CONICET-UBA, Institut Franco-Argentin d'Études sur le Climat et ses Impacts (IRL 3351 IFAECI), C1428EGA CABA, Argentina.
Significant changes in a system's dynamics can be understood through modifications in the topological structure of its flow in phase space. In the Earth's climate system, such changes are often referred to as tipping points. One of the large-scale components that may pass a tipping point is the Atlantic Meridional Overturning Circulation.
View Article and Find Full Text PDFJ Inorg Biochem
March 2025
Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina; Instituto de Química Física de Los Materiales, Medio Ambiente y Energía (INQUIMAE), CONICET-Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina. Electronic address:
Here, we show that the replacement of the distal residues Asp and/or Arg of the DyP peroxidases from Bacillus subtilis and Pseudomonas putida results in functional enzymes, albeit with spectroscopically perturbed active sites. All the enzymes can be activated either by the addition of exogenous HO or by in situ electrochemical generation of the reactive oxygen species (ROS) OH, O and HO. The latter method leads to broader and upshifted pH-activity profiles.
View Article and Find Full Text PDFEndocrine
November 2024
Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología, Biotecnología y Genética/Cátedra de Genética, Buenos Aires, Argentina.
DICER1 syndrome is an autosomal-dominant disorder that results in malignant or benign tumors. A number of distinct pathogenic germline and somatic variants have been identified as causing multinodular goiter (MNG). The purpose of the present study was to identify and characterize the genetic cause underlying the familial form of MNG through a whole-exome sequencing (WES) analysis in an Argentine family with three affected siblings.
View Article and Find Full Text PDFAutophagy
February 2025
Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China.
Reticulophagy selectively degrades fragments of the endoplasmic reticulum (ER) through macroautophagy/autophagy to maintain ER homeostasis. The deficiency of reticulophagy results in the unfolded protein response (UPR), which is a crucial clue to the pathogenesis of inflammatory diseases. However, the detailed mechanism underlying the cross-regulation between reticulophagy and inflammatory diseases remains largely unclear.
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