Examination of respiratory syncytial virus fusion protein proteolytic processing and roles of the P27 domain.

Autor:	Neal HE; Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky, USA., Barrett CT; Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky, USA., Edmonds K; Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky, USA., Moncman CL; Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky, USA., Dutch RE; Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky, USA.
Jazyk:	angličtina
Zdroj:	Journal of virology [J Virol] 2024 Dec 17; Vol. 98 (12), pp. e0163924. Date of Electronic Publication: 2024 Nov 07.
DOI:	10.1128/jvi.01639-24
Abstrakt:	The respiratory syncytial virus (RSV) fusion protein (F) facilitates virus-cell membrane fusion, which is critical for viral entry, and cell-cell fusion. In contrast to many type I fusion proteins, RSV F must be proteolytically cleaved at two distinct sites to be fusogenic. Cleavage at both sites results in the release of a 27 amino-acid fragment, termed Pep27. We examined proteolytic processing and the role of Pep27 for RSV F from both RSV A2 and RSV B9320 laboratory-adapted strains, allowing important comparisons between A and B clade F proteins. F from both clades was cleaved at both sites, and pulse-chase analysis indicated that cleavage at both sites occurs early after synthesis, most likely within the secretory pathway. Mutation of either site to alter the furin recognition motif blocked cell-cell fusion activity. To assess the role of Pep27 in F processing and expression, we deleted the Pep27 fragment, but preserved the cleavage sites. Deletion of Pep27 reduced F surface expression and cell-cell fusion. Two conserved N-linked glycosylation sites within Pep 27 are present in both the RSV A2 and RSV B9320 F. Randomization of the Pep27 sequence, while conserving the two N-liked glycosylation sites, did not significantly change surface expression, and only modestly reduced cell-cell fusion. However, the disruption of either Pep27 glycosylation site reduced cell-cell fusion. This work clarifies the timing of RSV F proteolytic cleavage and offers insight into the crucial role the N-linked glycosylation sites within Pep27 play in the biological function of F. Competing Interests: The authors declare no conflict of interest.
Databáze:	MEDLINE
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