The alphaherpesvirus US3/ORF66 protein kinases direct phosphorylation of the nuclear matrix protein matrin 3.
The protein kinase found in the short region of alphaherpesviruses, termed US3 in herpes simplex virus type 1 (HSV-1) and pseudorabies virus (PRV) and ORF66 in varicella-zoster virus (VZV), affects several viral and host cell processes, and its specific targets remain an area of active investigation. Reports suggesting that HSV-1 US3 substrates overlap with those of cellular protein kinase A (PKA) prompted the use of an antibody specific for phosphorylated PKA substrates to identify US3/ORF66 targets. HSV-1, VZV, and PRV induced very different substrate profiles that were US3/ORF66 kinase dependent. The predominant VZV-phosphorylated 125-kDa species was identified as matrin 3, one of the major nuclear matrix proteins. Matrin 3 was also phosphorylated by HSV-1 and PRV in a US3 kinase-dependent manner and by VZV ORF66 kinase at a novel residue (KRRRT150EE). Since VZV-directed T150 phosphorylation was not blocked by PKA inhibitors and was not induced by PKA activation, and since PKA predominantly targeted matrin 3 S188, it was concluded that phosphorylation by VZV was PKA independent. However, purified VZV ORF66 kinase did not phosphorylate matrin 3 in vitro, suggesting that additional cellular factors were required. In VZV-infected cells in the absence of the ORF66 kinase, matrin 3 displayed intranuclear changes, while matrin 3 showed a pronounced cytoplasmic distribution in late-stage cells infected with US3-negative HSV-1 or PRV. This work identifies phosphorylation of the nuclear matrix protein matrin 3 as a new conserved target of this kinase group.
Graduate Program in Molecular Virology and Microbiology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
Angela
A
Erazo
Michael B
MB
Yee
Bruce W
BW
Banfield
Paul R
PR
Kinchington
D018138:Alphaherpesvirinae / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D005347:Fibroblasts / Q000821:virology; D005786:Gene Expression Regulation; D018259:Herpesvirus 1, Human / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D011558:Herpesvirus 1, Suid / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D014645:Herpesvirus 3, Human / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000821:virology; D034521:Nuclear Matrix-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D016366:Open Reading Frames / Q000502:physiology*; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism*
C518587:MATR3 protein, human; D034521:Nuclear Matrix-Associated Proteins; D016601:RNA-Binding Proteins; D014764:Viral Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; C095207:US3 protein, Human herpesvirus 1