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Multiple congenital contractures (MCC) comprise a number of rare, non‐progressive conditions displaying marked phenotypic and etiologic heterogeneity. A genetic cause can be established in approximately half of the affected individuals, attributed to genetic defects in the formation and functioning of the central and peripheral nervous system, neuromuscular junctions, skeletal muscles, and connective tissue. Ubiquitin‐specific protease 14 (USP14) encodes a major proteasome‐associated deubiquitinating enzyme with an established dual role as an inhibitor and an activator of proteolysis, maintaining protein homeostasis. Usp14‐deficient mice show a phenotype similar to lethal human MCC phenotypes, with callosal anomalies, muscle wasting, and early lethality, attributed to neuromuscular junction defects due to decreased monomeric ubiquitin pool. We describe a new, autosomal recessive MCC phenotype in three fetuses from two different branches of a consanguineous family, presenting with distal arthrogryposis, underdevelopment of the corpus callosum, and dysmorphic facial features. Exome sequencing identified a biallelic 4‐bp deletion (c.233_236delTTCC; p.Leu78Glnfs*11, SCV002028347) in USP14, and sequencing of family members showed segregation with the phenotype. RT‐qPCR experiment in an unaffected heterozygote revealed that mutant USP14 was expressed, indicating that abnormal transcript escapes nonsense‐mediated mRNA decay. We propose that herein described fetuses represent the first human phenotype of USP14 loss, with callosal anomalies and/or cortical malformations, multiple contractures, and recognizable dysmorphic facial features. [ABSTRACT FROM AUTHOR]

Purpose: Ubiquitin ligase genes can act as oncogenes or tumor suppressor genes. They play a role in various diseases, including development and progression of breast cancer; the objective of this study was to evaluate the association of common variants in the ductal-epithelium-associated RING chromosome 1 (DEAR1) gene with breast cancer risk in a sample of Colombian population. Methods: We carried out a case-control study to investigate associations of variants in DEAR1 with breast cancer in women from Colombia. Single nucleotide polymorphisms (SNPs) rs584298, rs2927970, rs59983645, and rs599167 were genotyped in 1022 breast cancer cases and 1023 healthy controls using the iPLEX® and Kompetitive Allele Specific PCR (polymerase chain reaction) (KASP) method. The associations between SNPs and breast cancer were examined by conditional logistic regression. The associations between SNPs and epidemiological/histopathological variables were examined by multinomial logistic regression. Results: Associations were found between tag SNPs and breast cancer adjusted for the epidemiological risk factors rs584298 genotypes AG and GG (P =.048 and P =.004, respectively). The analysis of the disease characteristics showed that SNP rs584298 (genotype AG) (P =.015) shows association with progesterone receptor (PR) status and (genotype AA) (P =.048) shows association with human epidermal growth factor receptor 2 (HER2) status. Conclusions: The SNP rs584298 in DEAR1 showed associations with breast cancer and the expression of HER2 receptor; when this receptor is amplified, the result is aggressive tumoral subtype and expression of PR receptor that is associated with high-proliferative tumor grade. Validation of this SNP is important to establish whether this variant or the tagged variant is the cause for the risk association showed. [ABSTRACT FROM AUTHOR]

Background: The ubiquitin-proteasome system (UPS) is an important pathway of proteolysis in pathologic hypertrophic cardiomyocytes. We hypothesize that MG132, a proteasome inhibitor, might prevent hypertrophic cardiomyopathy (CMP) by blocking the UPS. Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and androgen receptor (AR) have been reported to be mediators of CMP and heart failure. This study drew upon pathophysiologic studies and the analysis of NF-κB and AR to assess the cardioprotective effects of MG132 in a left ventricular hypertrophy (LVH) rat model. Methods: We constructed a transverse aortic constriction (TAC)-induced LVH rat model with 3 groups: sham (TAC-sham, n=10), control (TAC-cont, n=10), and MG132 administration (TAC-MG132, n=10). MG-132 (0.1 mg/kg) was injected for 4 weeks in the TAC-MG132 group. Pathophysiologic evaluations were performed and the expression of AR and NF-κB was measured in the left ventricle. Results: Fibrosis was prevalent in the pathologic examination of the TAC-cont model, and it was reduced in the TAC-MG132 group, although not significantly. Less expression of AR, but not NF-κB, was found in the TAC-MG132 group than in the TAC-cont group (p＜0.05). Conclusion: MG-132 was found to suppress AR in the TAC-CMP model by blocking the UPS, which reduced fibrosis. However, NF- κB expression levels were not related to UPS function.

A well-defined co-translational pathway couples the synthesis and translocation of nascent polypeptides into and across the membrane of the endoplasmic reticulum (ER), thereby minimizing the possibility of the hydrophobic signals and transmembrane domains that such proteins contain from being exposed to the cytosol. Nevertheless, a proportion of these co-translational substrates may fail to reach the ER, and therefore mislocalize to the cytosol where their intrinsic hydrophobicity makes them aggregation-prone. A range of hydrophobic precursor proteins that employ alternative, post-translational, routes for ER translocation also contribute to the cytosolic pool of mislocalized proteins (MLPs). In this review, we detail how mammalian cells can efficiently deal with these MLPs by selectively targeting them for proteasomal degradation. Strikingly, this pathway for MLP degradation is regulated by cytosolic components that also facilitate the TRC40-dependent, post-translational, delivery of tail-anchored membrane proteins (TA proteins) to the ER. Among these components are small glutamine-rich tetratricopeptide repeat-containing protein α (SGTA) and Bcl-2-associated athanogene 6 (BAG6), which appear to play a decisive role in enforcing quality control over hydrophobic precursor proteins that have mislocalized to the cytosol, directing them to either productive membrane insertion or selective ubiquitination and proteasomal degradation. [ABSTRACT FROM AUTHOR]

Background: The observed mutations in cancer are the result of ~30 mutational processes, which stamp particular mutational signatures (MS). Nevertheless, it is still not clear which genomic alterations correlate to several MS. Here, a method to analyze associations of genomic data with MS is presented and applied to The Cancer Genome Atlas breast cancer data revealing promising associations. Methods: The MS were discretized into clusters whose extremes were statistically associated with mutations, copy number, and gene expression data. Results: Known associations for apolipoprotein B editing complex (APOBEC) and for BRCA1 and BRCA2 support the proposal. For BRCA1/2, mutations in ARAP3, three focal deletions, and one amplification were detected. Around 50 mutated genes for the two APOBEC signatures were identified including three kinesins (KIF13A, KIF1B, KIF4A), three ubiquitins (USP45, UBR4, UBR1), and two demethylases (KDM5B, KDM5C) among other genes also connected to DNA damage pathways. The results suggest novel roles for other genes currently not involved in DNA repair. The altered expression program was very high for the BRCA1/2 signature, high for APOBEC signature 13 clearly associated to immune response, and low for APOBEC signature 2. The remaining signatures show scarce associations. Conclusion: Specific genetic alterations can be associated with particular MS. [ABSTRACT FROM AUTHOR]