IMMUNOLOGY
Selective targeting of ITK blocks multiple steps of HIV replication
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*Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892;
Center for Molecular Immunology and Infectious Diseases, Integrated Biosciences Graduate Program, Department of Veterinary Sciences, Pennsylvania State University, University Park, PA 16802;
Chemical Biology Core Facility, National Institute of Diabetes, Digestive and Kidney Disorders, National Institutes of Health, Bethesda, MD 20892;
¶NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892; and
Center for HIV/AIDS Care and Research, Department of Medicine, Boston University School of Medicine, Boston, MA 02118
Edited by Stephen P. Goff, Columbia University College of Physicians and Surgeons, New York, NY, and approved March 19, 2008 (received for review October 10, 2007)
Abstract
Treatment for HIV has relied on the use of antiretroviral agents that can be subject to the development of resistant viruses. The study of inhibitors directed against cellular proteins required for HIV replication is therefore of growing interest. Inducible T cell kinase (ITK) is a Tec family tyrosine kinase that regulates T cell receptor (TCR)-induced activation of PLC
-1, Ca2+ mobilization and transcription factor activation, and actin rearrangement downstream of both TCR and chemokine receptors. Because productive infection of T cells with HIV requires T cell activation, chemokine receptors and actin reorganization, we asked whether ITK affects HIV infection using ITK-specific siRNA, a kinase-inactive ITK mutant or an ITK inhibitor. We demonstrate that loss of ITK function resulted in marked reductions in intracellular p24 levels upon HIV infection. Loss of ITK function after establishment of HIV infection also decreased virus spread within the culture. Inhibition of ITK did not affect expression of the HIV coreceptors CD4 or CXCR4 but partially blocked HIV viral entry, an effect that correlated with decreased actin polarization to gp120. Additionally, ITK was required for efficient HIV transcription, and overexpression of ITK increased both viral transcription and virus-like particle formation. Our data suggest that inhibition of ITK blocks HIV infection by affecting multiple steps of HIV replication.
T cell signaling | transcription | tyrosine kinase | viral entry | kinase inhibitors
Author contributions: J.A.R. and G.M.S. contributed equally to this work; J.A.R., G.M.S., J.-K.J., C.J.T., A.A., A.J.H., and P.L.S. designed research; J.A.R. and G.M.S. performed research; J.-K.J. and C.J.T. contributed new reagents/analytic tools; J.A.R., G.M.S., A.J.H., and P.L.S. analyzed data; and J.A.R., G.M.S., A.J.H., and P.L.S. wrote the paper.
Conflict of interest statement: A patent has been filed for ITK (patent application: E-151-2006/0-US-01; NIHA-0291, filed March 27, 2007).
This article is a PNAS Direct Submission.
||To whom correspondence may be addressed. E-mail: andrew.henderson{at}bmc.org or pams{at}nhgri.nih.gov
© 2008 by The National Academy of Sciences of the USA
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