Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.


Logo for

PNAS 109 (19): 1163-1172

Copyright © 2012 by the National Academy of Sciences.



Kaposi’s sarcoma-associated herpesvirus interacts with EphrinA2 receptor to amplify signaling essential for productive infection

Sayan Chakraborty, Mohanan Valiya Veettil, Virginie Bottero, and Bala Chandran1

H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064

1To whom correspondence should be addressed. E-mail: bala.chandran{at}

Abstract: Kaposi’s sarcoma-associated herpesvirus (KSHV), etiologically associated with Kaposi’s sarcoma, uses integrins (α3β1, αVβ3, and αVβ5) and associated signaling to enter human dermal microvascular endothelial cells (HMVEC-d), an in vivo target of infection. KSHV infection activated c-Cbl, which induced the selective translocation of KSHV into lipid rafts (LRs) along with the α3β1, αVβ3, and xCT receptors, but not αVβ5. LR-translocated receptors were monoubiquitinated, leading to productive macropinocytic entry, whereas non-LR–associated αVβ5 was polyubiquitinated, leading to clathrin-mediated entry that was targeted to lysosomes. Because the molecule(s) that integrate signal pathways and productive KSHV macropinocytosis were unknown, we immunoprecipitated KSHV-infected LR fractions with anti-α3β1 antibodies and analyzed them by mass spectrometry. The tyrosine kinase EphrinA2 (EphA2), implicated in many cancers, was identified in this analysis. EphA2 was activated by KSHV. EphA2 was also associated with KSHV and integrins (α3β1 and αVβ3) in LRs early during infection. Preincubation of virus with soluble EphA2, knockdown of EphA2 by shRNAs, or pretreatment of cells with anti-EphA2 monoclonal antibodies or tyrosine kinase inhibitor dasatinib significantly reduced KSHV entry and gene expression. EphA2 associates with c-Cbl-myosin IIA and augmented KSHV-induced Src and PI3-K signals in LRs, leading to bleb formation and macropinocytosis of KSHV. EphA2 shRNA ablated macropinocytosis-associated signaling events, virus internalization, and productive nuclear trafficking of KSHV DNA. Taken together, these studies demonstrate that the EphA2 receptor acts as a master assembly regulator of KSHV-induced signal molecules and KSHV entry in endothelial cells and suggest that the EphA2 receptor is an attractive target for controlling KSHV infection.

Key Words: virus entry • productive endocytosis • receptor tyrosine kinase


The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

See full research article on page E1163 of

Cite this Author Summary as: PNAS 10.1073/pnas.1119592109.

Inhibition of Dengue Virus Replication by a Class of Small-Molecule Compounds That Antagonize Dopamine Receptor D4 and Downstream Mitogen-Activated Protein Kinase Signaling.
J. L. Smith, D. A. Stein, D. Shum, M. A. Fischer, C. Radu, B. Bhinder, H. Djaballah, J. A. Nelson, K. Fruh, and A. J. Hirsch (2014)
J. Virol. 88, 5533-5542
   Abstract »    Full Text »    PDF »
Reactive Oxygen Species Are Induced by Kaposi's Sarcoma-Associated Herpesvirus Early during Primary Infection of Endothelial Cells To Promote Virus Entry.
V. Bottero, S. Chakraborty, and B. Chandran (2013)
J. Virol. 87, 1733-1749
   Abstract »    Full Text »    PDF »

To Advertise     Find Products

Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882