Biology subjects

Cryle, M.

Publications and source records attributed to Cryle, M..

3 recordsLinked to original sources

bioRxiv2024

SRP19 and the protein secretion machinery is a targetable vulnerability in cancers with APC loss

Adenomatous Polyposis Coli (APC) is a tumour suppressor that is frequently lost in colorectal and other cancers. A common mechanism for APC loss includes heterozygous APC deletion. Here, we show that SRP19, is located near APC and is often co-deleted in these tumours. Heterozygous APC/SRP19 loss leads to lower levels of SRP19 mRNA and protein. Consequently, cells with APC/SRP19 loss are vulnerable to partial suppression of SRP19. We show that SRP19 loss is a unique vulnerability since SRP19 is rate limiting for the formation of the Signal Recognition Particle (SRP), a complex that mediates translocation of proteins to the ER. Consistent with these observations, partial SRP19 knock-down or low dose Arsenic Trioxide treatment induces ER stress and inhibits proliferation in APC/SRP19 loss cancers. Our work identifies a new strategy to treat cancers with APC/SRP19 heterozygous deletions and provides a framework for identifying vulnerabilities associated with loss of a tumour suppressor.

cancer biology↗

bioRxiv2023

Phylogenetic distance and structural diversity directing a reclassification of glycopeptide antibiotics

Glycopeptide antibiotics (GPAs) are key agents against multidrug-resistant Gram-positive pathogens, yet both the term "glycopeptide" and the current GPA type I-V classification framework have become increasingly strained as structurally and mechanistically divergent members continue to be discovered. In particular, compounds historically grouped as "type V GPAs" differ from classical GPAs in features such as glycosylation, peptide length, and reported mode of action, raising the question of whether they belong to the same natural product class. Here, a curated dataset of GPA-associated biosynthetic gene clusters (BGCs) is analysed by combining fingerprint similarity of the products with phylogenetic analysis of the BGCs. Fingerprint-based structural similarity networks and BGC similarity comparisons reveal a pronounced separation between classical lipid II-binding GPAs (types I-IV) and type V GPAs. Multi-locus phylogenetic analyses of conserved biosynthetic components further support two deeply divergent evolutionary subclasses, consistent with subclass-specific biosynthetic signatures. Together, these results motivate a revised, unambiguous framework in which the broader class is termed xyclopeptides, comprising the subclasses dalabactins (legacy GPA types I-IV) and murobactins (legacy type V).

genetics↗

bioRxiv2020

Cellular and structural basis of synthesis of the unique intermediate dehydro-F420-0 in mycobacteria

F420 is a low-potential redox cofactor used by diverse bacteria and archaea. In mycobacteria, this cofactor has multiple roles, including adaptation to redox stress, cell wall biosynthesis, and activation of the clinical antitubercular prodrugs pretomanid and delamanid. A recent biochemical study proposed a revised biosynthesis pathway for F420 in mycobacteria; it was suggested that phosphoenolpyruvate served as a metabolic precursor for this pathway, rather than 2-phospholactate as long proposed, but these findings were subsequently challenged. In this work, we combined metabolomic, genetic, and structural analyses to resolve these discrepancies and determine the basis of F420 biosynthesis in mycobacterial cells. We show that, in whole cells of Mycobacterium smegmatis, phosphoenolpyruvate rather than 2-phospholactate stimulates F420 biosynthesis. Analysis of F420 biosynthesis intermediates present in M. smegmatis cells harboring genetic deletions at each step of the biosynthetic pathway confirmed that phosphoenolpyruvate is then used to produce the novel precursor compound dehydro-F420-0. To determine the structural basis of dehydro-F420-0 production, we solved high-resolution crystal structures of the enzyme responsible (FbiA) in apo, substrate, and product bound forms. These data show the essential role of a single divalent cation in coordinating the catalytic pre-complex of this enzyme and demonstrate that dehydro-F420-0 synthesis occurs through a direct substrate transfer mechanism. Together, these findings resolve the biosynthetic pathway of F420 in mycobacteria and have significant implications for understanding the emergence of antitubercular prodrug resistance.

biochemistry↗