Computational and Structural Analysis to Assess the Pathogenicity of Bardet-Biedl Syndrome Related Missense Variants Identified in Bardet-Biedl Syndrome 10 Gene (BBS10)

Coevolution-based computational approach to detect resistance mechanism of epidermal growth factor receptor

Tyrosine kinase epidermal growth factor receptor (EGFR) correlates the neoplastic cell metastasis, angiogenesis, neoplastic incursion, and apoptosis. Due to the involvement of EGFR in these biological processes, it becomes a most potent target for treating non-small cell lung cancer (NSCLC). The tyrosine kinase inhibitors (TKI) have endorsed high efficacy and anticipation to patients but unfortunately, within a year of treatment, drug targets develop resistance due to mutations. The present study detected the compensatory mutations in EGFR to know the evolutionary mechanism of drug resistance. The results of this study demonstrate that compensatory mutations enlarge the drug-binding pocket which may lead to the altered orientation of the ligand (gefitinib and erlotinib) causing drug resistance. This indicates that coevolutionary forces play a significant role in fine-tuning the structure of EGFR protein against the drugs. The analysis provides insight into the evolution-induced structural aspects of drug resistance changes in EGFR which in turn be useful in designing drugs with better efficacy.

Evaluation of Pathogenicity and Structural Alterations for the Mutations Identified in the Conserved Region of the C-Terminal Kinase Domain of Human-Ribosomal S6 Kinase 1

Human-ribosomal s6 kinase 1 (h-RSK1) is an effector kinase of the Ras/MAPK signaling pathway, which is involved in the regulation of the cell cycle, proliferation, and survival. RSKs comprise two functionally distinct kinase domains at the N-terminal (NTKD) and C-terminal (CTKD) separated by a linker region. The mutations in RSK1 may have the potential to provide an extra benefit to the cancer cell to proliferate, migrate, and survive. The present study focuses on evaluating the structural basis for the missense mutations identified at the C-terminal kinase domain of human-RSK1. A total of 139 mutations reported on RSK1 were retrieved from cBioPortal, where 62 were located at the CTKD region. Furthermore, 10 missense mutations Arg434Pro, Thr701Met, Ala704Thr, Arg725Trp, Arg726Gln, His533Asn, Pro613Leu, Ser720Cys, Arg725Gln, and Ser732Phe were predicted to be deleterious using in silico tools. To our observation, these mutations are located in the evolutionarily conserved region of RSK1 and shown to alter the inter- and intramolecular interactions and also the conformational stability of RSK1-CTKD. The molecular dynamics (MD) simulation study further revealed that the five mutations Arg434Pro, Thr701Met, Ala704Thr, Arg725Trp, and Arg726Gln showed maximum structural alterations in RSK1-CTKD. Thus, based on the in silico and MD simulation analysis, it can be concluded that the reported mutations may serve as potential candidates for further functional studies.

Next-Generation Sequencing (NGS) Analysis Illustrates the Phenotypic Variability of Collagen Type IV Nephropathies

Mutations in COL4A3-A5 cause a spectrum of glomerular disorders, including thin basement membrane nephropathy (TBMN) and Alport syndrome (AS). The wide application of next-generation sequencing (NGS) in the last few years has revealed that mutations in these genes are not limited to these clinical entities. In this study, 176 individuals with a clinical diagnosis of inherited kidney disorders underwent an NGS-based analysis to address the underlying cause; those who changed or perfected the clinical diagnosis after molecular analysis were selected. In 5 out of 83 individuals reaching a molecular diagnosis, the genetic result was unexpected: three individuals showed mutations in collagen type IV genes. These patients showed the following clinical pictures: (1) familial focal segmental glomerulosclerosis; (2) end-stage renal disease (ESRD) diagnosed incidentally in a 49-year-old man, with diffuse cortical calcifications on renal imaging; and (3) dysmorphic and asymmetric kidneys with multiple cysts and signs of tubule-interstitial defects. Genetic analysis revealed rare heterozygote/compound heterozygote COL4A4-A5 variants. Our study highlights the key role of NGS in the diagnosis of inherited renal disorders and shows the phenotype variability in patients carrying mutations in collagen type IV genes.