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

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.virus entry | productive endocytosis | receptor tyrosine kinase

Entry of Classical Swine Fever Virus into PK-15 Cells via a pH-, Dynamin-, and Cholesterol-Dependent, Clathrin-Mediated Endocytic Pathway That Requires Rab5 and Rab7

“…Various viruses enter host cells through lipid rafts in which cholesterol is the predominant component (49)(50)(51). The lipid raft is readily disrupted if membrane cholesterol is selectively extracted by pharmacological agents such as M␤CD or filipin (52,53).…”

Transcriptome Analysis of Kaposi's Sarcoma-Associated Herpesvirus during De Novo Primary Infection of Human B and Endothelial Cells

“…KSHV infects a variety of cellular targets and establishes a latent infection, generally by 24 hpi (14,(16)(17)(18)(19)(20). To understand the differential expression of viral transcripts early during infection, PBMCs, CD14 ϩ cells, and TIVE cells were de novo infected with KSHV for different lengths of time (0,4,24,48,72, and 120 h).…”

“…The mechanisms by which KSHV successfully circumvents these obstacles are beginning to be resolved. During de novo infections, KSHV generally establishes latency by 24 h postinoculation (hpi) in cell culture systems (14,(16)(17)(18)(19)(20). However, very early, immediately after a de novo infection, KSHV undergoes a limited initial burst of lytic transcript accumulation (14).…”

Kaposi sarcoma–associated herpesvirus: immunobiology, oncogenesis, and therapy

“…PELs are also extremely sensitive to NF-κB pathway inhibitors such as bortezomib (186,187), and a clinical trial with adjuvant bortezomib is ongoing. Other targets with encouraging preclinical results are NOTCH (188)(189)(190)(191)(192), and the KSHV receptor, ephrin receptor A2 (EphA2) (193)(194)(195).…”