The HSV-2 protein ICP10PK upregulates/activates the function/survival related proteins Rap1 and adenylate cyclase in neuronal cultures

• Published in: Journal of neurovirology Vol. 12; pp. 76 - 77
• Main Authors: Smith, C C, Wales, S Q, Aurelian, L
• Format: Journal Article
• Language: English
• Published: 01.05.2006
• Subjects: Herpes simplex virus 2
• ISSN: 1355-0284

The HSV-2 protein ICP10 PK is neuroprotective. DNA array analyses comparing mock infected cells to cells infected with HSV-2 or an ICP10PK deleted mutant (deltaPK) identified 14 transcripts that were upregulated by HSV-2 but not deltaPK (mean difference > 5 fold) including Rap1 and adenylate cyclase. Rap1 is a Ras like GTPase that is involved in neuronal plasticity, calcium channel upregulation, excitability control and LTP. Adenylate cyclase generates c-AMP causing activation of PKA and CREB, which are involved in neurotrophin-mediated survival. RT-PCR and/or immunoblotting confirmed that Rap1 and adenylate cyclase were upregulated in primary hippocampal cultures by HSV-2 or the revertant virus [HSV-2(R)], but not deltaPK. Rap1 upregulation was seen at 30 min, and was still visible at 24 hrs p.i. Immunocomplex kinase assays indicated that B-Raf kinase was activated in HSV-2 but not deltaPK infected cultures, and pull-down experiments confirmed that Rap-1 bound the activated B-Raf. Adenylate cyclase levels were increased and CREB was activated (phosphorylated) in neuronally differentiated PC12 cells that constitutively express ICP10PK, but not in parental PC12 cells or PC12 cells that express a kinase negative ICP10PK mutant. CREB activation was decreased with the PKA inhibitor H89. The data indicate that ICP10PK upregulates Rap1 and adenylate cyclase in neuronal cells contributing to their survival and function.