Biology subjects

Bhagwat, A. M.

Publications and source records attributed to Bhagwat, A. M..

4 recordsLinked to original sources

bioRxiv2023

Intrinsically Disordered Regions Promote Protein Refoldability and Facilitate Retrieval from Biomolecular Condensates

Many eukaryotic proteins contain intrinsically disordered regions (IDRs) that intersperse globular folded domains, in contrast with bacterial proteins which are typically highly globular1, 2. Recent years have seen great progress in identifying biological functions associated with these elusive protein sequence: in specific cases, they mediate liquid liquid phase separation3, perform molecular recognition4, or act as sensors to changes in the environment5. Nevertheless, only a small number of IDRs have annotated functions6 despite their presence in 64% of yeast proteins,7 stimulating some to question what general purpose they may serve8, 9. Here, by interrogating the refoldability of two fungal proteomes (Saccharomyces cerevisiae and Neurosporra crassa), we show that IDRs render their host proteins more refoldable from the denatured state, allowing them to cohere more closely to Anfinsens thermodynamic hypothesis10, 11. The data provide an exceptionally clear picture of which biophysical and topological characteristics enable refoldability. Moreover, we find that almost all yeast proteins that partition into stress granules during heat shock are refoldable, a finding that holds for other condensates such as P-bodies and the nucleolus. Finally, we find that the Hsp104 unfoldase12 is the principal actor in mediating disassembly of heat stress granules and that the efficiency with which condensed proteins are returned to the soluble phase is also well explained by refoldability. Hence, these studies establish spontaneous refoldability as an adaptive trait that endows proteins with the capacity to reform their native soluble structures following their extraction from condensates. Altogether, our results provide an intuitive model for the function of IDRs in many multidomain proteins and clarifies their relationship to the phenomenon of biomolecular condensation.

biochemistry↗

bioRxiv2020

multicrispr: fast gRNA designer enables prime editing and parallel targeting of thousands of targets

Targeting the coding genome to introduce single nucleotide deletions/insertions via Crispr/Cas9 technology has become a standard procedure in recent years. It has quickly spawned a multitude of methods such as Prime Editing, Crispr/Cas9 assisted APEX proximity labeling of proteins, or homology directed repair (HDR), for which supporting bioinformatic tools are, however, lagging behind. New applications often require specific guide-RNA (gRNA) design functionality, and a generic gRNA design tool is critically missing. Here we review gRNA designer software and introduce multicrispr, an R based tool intended to design individual gRNAs as well as gRNA libraries targeting many genomic loci in parallel. The package is easy to use, detects, scores and filters gRNAs on both efficiency and specificity, visualizes and aggregates results per target or Crispr/Cas9 sequence, and finally returns both genomic ranges as well as sequences of preferred, off target-free gRNAs. In order to be generic, multicrispr defines and implements a genomic arithmetics framework as a basis for facile adaptation to techniques yet to arise. Its performance and new gRNA design concepts such as target set specific filtering for gRNA libraries render multicrispr the tool of choice when dealing with screening-like approaches.

bioinformatics↗

bioRxiv2018

Myh10 deficiency leads to defective extracellular matrix remodeling and pulmonary disease

Impaired alveolar formation and maintenance are features of many pulmonary diseases that are associated with significant morbidity and mortality. In a forward genetic screen for modulators of mouse lung development, we identified the non-muscle myosin II heavy chain gene, Myh10. Myh10 mutant pups exhibit cyanosis and respiratory distress, and die shortly after birth from differentiation defects in alveolar epithelium and mesenchyme. From omics analyses and follow up studies, we find decreased Thrombospondin expression accompanied with increased matrix metalloproteinase activity in both mutant lungs and cultured mutant fibroblasts, as well as disrupted extracellular matrix (ECM) remodeling. Loss of Myh10 specifically in mesenchymal cells results in ECM deposition defects and alveolar simplification. Notably, MYH10 expression is down-regulated in the lung of emphysema patients. Altogether, our findings reveal critical roles for Myh10 in alveologenesis at least in part via the regulation of ECM remodeling, which may contribute to the pathogenesis of emphysema.

developmental biology↗

bioRxiv2018

Accelerated lipid catabolism and autophagy are cancer survival mechanisms under inhibited glutaminolysis

Suppressing glutaminolysis does not always induce cancer cell death in glutamine-dependent tumors because cells may switch to alternative energy sources. To reveal compensatory metabolic pathways, we investigated the metabolome-wide cellular response to inhibited glutaminolysis. We conducted metabolic profiling in the triple-negative breast cancer cell line MB-MDA-231, treated with different dosages of glutaminase inhibitor C.968 at multiple time points. We found that multiple molecules involved in lipid catabolism responded directly to glutamate deficiency as a presumed compensation for energy deficit. Accelerated lipid catabolism, together with oxidative stress induced by glutaminolysis inhibition, triggered autophagy. We therefore simultaneously inhibited glutaminolysis and autophagy, which induced cancer cell death. Our study emphasizes the potential of non-targeted metabolomics to characterize and identify metabolic escape mechanisms contributing to cancer cell survival under treatment. Our findings add to the increasing evidence that combined inhibition of glutaminolysis and autophagy may be effective in glutamine-addicted cancers.

cancer biology↗