The K15 protein of Kaposi's sarcoma-associated herpesvirus recruits the endocytic regulator intersectin 2 through a selective SH3 domain interaction.
Kaposi's sarcoma-associated herpesvirus, also known as human herpesvirus 8, is closely associated with several cancers including Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. The rightmost end of the KSHV genome encodes a protein, K15, with multiple membrane-spanning segments and an intracellular carboxy-terminal tail that contains several conserved motifs with the potential to recruit interaction domains (i.e., SH2, SH3, TRAF) of host cell proteins. K15 has been implicated in downregulating B cell receptor (BCR) signaling through its conserved motifs and may thereby play a role in maintaining viral latency and/or preventing apoptosis of the infected B cells. However, K15's mode of action is largely unknown. We have used mass spectrometry, domain and peptide arrays, and surface plasmon resonance to identify binding partners for a conserved proline-rich sequence (PPLP) in the K15 cytoplasmic tail. We show that the PPLP motif selectively binds the SH3-C domain of an endocytic adaptor protein, Intersectin 2 (ITSN2). This interaction can be observed both in vitro and in cells, where K15 and ITSN2 colocalize to discrete compartments within the B cell. The ability of K15 to associate with ITSN2 suggests a new role for the K15 viral protein in intracellular protein trafficking.
Lim
Caesar S
CS
Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada.
Seet
Bruce T
BT
Ingham
Robert J
RJ
Gish
Gerald
G
Matskova
Liudmila
L
Winberg
Gösta
G
Ernberg
Ingemar
I
Pawson
Tony
T
D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism*; D020816:Amino Acid Motifs / Q000502:physiology; D000818:Animals; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D004705:Endocytosis / Q000235:genetics*; D019288:Herpesvirus 8, Human / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D013058:Mass Spectrometry; D008958:Models, Molecular; D040081:Protein Array Analysis; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D011993:Recombinant Fusion Proteins; D012680:Sensitivity and Specificity; D015398:Signal Transduction / Q000502:physiology; D020349:Surface Plasmon Resonance; D014162:Transfection; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D018909:src Homology Domains / Q000502:physiology*
D033942:Adaptor Proteins, Vesicular Transport; C509776:ITSN2 protein, human; C402642:K15 protein, Human herpesvirus 8; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins