Biology subjects

Notari, L.

Publications and source records attributed to Notari, L..

3 recordsLinked to original sources

bioRxiv2025

A neoantigen-microbead platform for personalized T cell cancer vaccination

Colorectal cancer (CRC) is a leading cause of cancer mortality and is characterized by a high tumor mutational burden, making it responsive to immunotherapy. We developed a bioinformatic and manufacturing pipeline for personalized cancer vaccines and evaluated it in the MC38 colon adenocarcinoma mouse model. Thirty-six high-scoring neoantigens (NAGs) were identified by exome and transcriptome analysis, produced as six purified polypeptides, and coupled to paramagnetic beads. Intralymphatic vaccination of C57BL/6 mice with NAG beads induced robust NAG-specific T cell and antibody responses, resulting in significant inhibition of MC38 tumor growth. Treated tumors displayed increased necrosis and CD8+ T cell infiltration. Compared with soluble peptides, bead-coupled antigens elicited superior protection. Studies in T cell-deficient and antibody-depleted mice confirmed that both CD4+ and CD8+ T cells mediated the antitumor effect. These findings highlight the potential of NAG bead vaccination as an effective immunotherapy for CRC.

cancer biology↗

bioRxiv2020

Prion Protein Folding Mechanism Revealed by Pulling Force Studies

The mammalian prion protein (PrP) engages with the ribosome-Sec61 translocation channel complex to generate different topological variants that are either physiological, or involved in neurodegenerative diseases. Here, we describe cotranslational folding and translocation mechanisms of PrP coupled to a Xbp1-based arrest peptide (AP) as folding sensor, to measure forces acting on PrP nascent chain. Our data reveal two main pulling events followed by a minor third one exerted on the nascent chains during their translocation. Using those force landscapes, we show that a specific sequence within an intrinsically disordered region, containing a polybasic and glycine-proline rich residues, modulates the second pulling event by interacting with TRAP complex. This work also delineates the sequence of events involved in generation of PrP toxic transmembrane topologies during its synthesis. Our results shed new insight into the folding of such topological complex protein, where marginal pulling by the signal sequence, together with the downstream sequence in the mature domain, primarily drives an overall inefficient translocation resulting in the nascent chain to adopt other topologies.

biochemistry↗

bioRxiv2018

Cotranslational folding of a pentarepeat β-helix protein

It is becoming increasingly clear that many proteins start to fold cotranslationally, before the entire polypeptide chain has been synthesized on the ribosome. One class of proteins that a priori would seem particularly prone to cotranslational folding is repeat proteins, i.e., proteins that are built from an array of nearly identical sequence repeats. However, while the folding of repeat proteins has been studied extensively in vitro with purified proteins, only a handful of studies have addressed the issue of cotranslational folding of repeat proteins. Here, we have determined the structure and studied the cotranslational folding of a {beta}-helix pentarepeat protein from the human pathogen Clostridium botulinum - a homolog of the Fluoroquinolone Resistance Protein MfpA - using an assay in which the SecM translational arrest peptide serves as a force sensor to detect folding events. We find that cotranslational folding of a segment corresponding to the first four of the eight {beta}-helix coils in the protein produces enough force to release ribosome stalling, and that folding starts when this unit is ~35 residues away from the P-site, near the distal end of the ribosome exit tunnel. An additional folding transition is seen when the whole PENT moiety emerges from the exit tunnel. The early cotranslational formation of a folded unit may be important to avoid misfolding events in vivo, and may reflect the minimal size of a stable {beta}-helix since it is structurally homologous to the smallest known {beta}-helix protein, a four-coil protein that is stable in solution.

molecular biology↗