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Chlamydia trachomatis is an obligate intracellular bacterium that causes a variety of diseases in humans. C. trachomatis has a complex developmental cycle that depends on host cells for replication, during which gene expression is tightly regulated. Here we identify two C. trachomatis proteases that possess deubiquitinating and deneddylating activities. We(More)
Like their normal hematopoietic stem cell counterparts, leukemia stem cells (LSCs) in chronic myelogenous leukemia (CML) and acute myeloid leukemia (AML) are presumed to reside in specific niches in the bone marrow microenvironment (BMM) and may be the cause of relapse following chemotherapy. Targeting the niche is a new strategy to eliminate persistent and(More)
The posttranslational modifier ubiquitin is encoded by a multigene family containing three primary members, which yield the precursor protein polyubiquitin and two ubiquitin moieties, Ub(L40) and Ub(S27), that are fused to the ribosomal proteins L40 and S27, respectively. The gene encoding polyubiquitin is highly conserved and, until now, those encoding(More)
Posttranslational modification of substrates by the small ubiquitin-like modifier, SUMO, regulates diverse biological processes, including transcription, DNA repair, nucleocytoplasmic trafficking, and chromosome segregation. SUMOylation is reversible, and several mammalian homologs of the yeast SUMO-specific protease Ulp1, termed SENPs, have been(More)
BACKGROUND The family of ubiquitin-like molecules (UbLs) comprises several members, each of which has sequence, structural, or functional similarity to ubiquitin. ISG15 is a homolog of ubiquitin in vertebrates and is strongly upregulated following induction by type I interferon. ISG15 can be covalently attached to proteins, analogous to ubiquitination and(More)
The addition of ubiquitin (Ub) and ubiquitin-like (Ubl) modifiers to proteins serves to modulate function and is a key step in protein degradation, epigenetic modification and intracellular localization. Deubiquitinating enzymes and Ubl-specific proteases, the proteins responsible for the removal of Ub and Ubls, act as an additional level of control over(More)
MOTIVATION The conjugation of ubiquitin to target molecules involves several enzymatic steps. Little is known about the specificity of ubiquitination. How E3 ligases select their substrate and which lysines are targeted for ubiquitin conjugation is largely an enigma. The object of this study is to identify preferred ubiquitination sites. Genetic approaches(More)
Ubiquitination is a post-translational modification implicated in a variety of cellular functions, including transcriptional regulation, protein degradation and membrane protein trafficking. Ubiquitin and the enzymes that act on it, although conserved and essential in eukaryotes, have not been well studied in parasites, despite sequencing of several(More)
BACKGROUND Ubiquitin and ubiquitin-like proteins (Ubl) are designed to modify polypeptides in eukaryotes. Covalent binding of ubiquitin or Ubls to substrate proteins can be reversed by specific hydrolases. One particular set of cysteine proteases, the CE clan, which targets ubiquitin and Ubls, has homologs in eukaryotes, prokaryotes, and viruses. FINDINGS(More)