Membrane-bound Merkel cell polyomavirus middle T protein constitutively activates PLCγ1 signaling through Src-family kinases.

Autor:	Peng WY; School of Medicine, Tsinghua University, Beijing 100084, China.; Cancer Virology Program, Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213., Abere B; Cancer Virology Program, Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213.; Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219., Shi H; Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219., Toland S; Cancer Virology Program, Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213., Smithgall TE; Cancer Virology Program, Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213.; Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219., Moore PS; Cancer Virology Program, Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213.; Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219., Chang Y; Cancer Virology Program, Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213.; Department of Pathology, University of Pittsburgh, Pittsburgh, PA 15213.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2023 Dec 19; Vol. 120 (51), pp. e2316467120. Date of Electronic Publication: 2023 Dec 11.
DOI:	10.1073/pnas.2316467120
Abstrakt:	Merkel cell polyomavirus (MCV or MCPyV) is an alphapolyomavirus causing human Merkel cell carcinoma and encodes four tumor (T) antigen proteins: large T (LT), small tumor (sT), 57 kT, and middle T (MT)/alternate LT open reading frame proteins. We show that MCV MT is generated as multiple isoforms through internal methionine translational initiation that insert into membrane lipid rafts. The membrane-localized MCV MT oligomerizes and promiscuously binds to lipid raft-associated Src family kinases (SFKs). MCV MT-SFK interaction is mediated by a Src homology (SH) 3 recognition motif as determined by surface plasmon resonance, coimmunoprecipitation, and bimolecular fluorescence complementation assays. SFK recruitment by MT leads to tyrosine phosphorylation at a SH2 recognition motif (pMT Y114 ), allowing interaction with phospholipase C gamma 1 (PLCγ1). The secondary recruitment of PLCγ1 to the SFK-MT membrane complex promotes PLCγ1 tyrosine phosphorylation on Y783 and activates the NF-κB inflammatory signaling pathway. Mutations at either the MCV MT SH2 or SH3 recognition sites abrogate PLCγ1-dependent activation of NF-κB signaling and increase viral replication after MCV genome transfection into 293 cells. These findings reveal a conserved viral targeting of the SFK-PLCγ1 pathway by both MCV and murine polyomavirus (MuPyV) MT proteins. The molecular steps in how SFK-PLCγ1 activation is achieved, however, differ between these two viruses. Competing Interests: Competing interests statement:The authors declare no competing interest.
Databáze:	MEDLINE
Externí odkaz:	Zobrazit plný text záznamu