Differential interaction of HIV-1 integrase and JPO2 with the C terminus of LEDGF/p75.
The transcriptional co-activator lens epithelium-derived growth factor (LEDGF) has been shown to protect cells against environmental stress. The protein has been implicated in auto-immunity and cancer, and is present in cells as the p52 or p75 splice variant. Recently, LEDGF/p75, but not p52, was identified as the prominent interaction partner of human immunodeficiency virus type 1 (HIV-1) integrase. This interaction of HIV-1 integrase with the C-terminal integrase-binding domain of LEDGF/p75 is crucial for HIV-1 replication. To gain insight into the cell biology of LEDGF/p75, we were interested in identifying cellular binding partners of its C-terminal domain. By yeast-two-hybrid screening with a CEMC7 cDNA-library, we were able to identify JPO2 as a binding partner of the C-terminal part of LEDGF/p75. The specific interaction between JPO2 and LEDGF/p75 was verified by pull-down, AlphaScreen, and co-immunoprecipitation. Competition assays using recombinant proteins show a mutually exclusive binding of either JPO2 or HIV-1 integrase to LEDGF/p75. However, differing mechanisms of binding were suggested by continuing interaction of JPO2 with some LEDGF/p75 mutants (I365A, D366A, F406A) that are totally defective for interaction with HIV-1 integrase. This finding is of significance for the development of specific inhibitors targeting only the interaction between LEDGF/p75 and HIV-1 integrase, without disturbing interaction with other cellular factors. Over-expression of JPO2 resulted in a modest but reproducible inhibition of HIV-1 replication, consistent with competition between integrase and JPO2 for binding to LEDGF/p75. Furthermore, JPO2 over-expression activated transcription from the HIV-1 LTR.
Molecular Medicine, KULeuven and IRC KULAK, Leuven, Belgium.
Koen
K
Bartholomeeusen
Jan
J
De Rijck
Katrien
K
Busschots
Linda
L
Desender
Rik
R
Gijsbers
Stéphane
S
Emiliani
Richard
R
Benarous
Zeger
Z
Debyser
Frauke
F
Christ
D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D015870:Gene Expression; D019427:HIV Integrase / Q000378:metabolism*; D015497:HIV-1 / Q000201:enzymology / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000378:metabolism*; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication; D015032:Zinc / Q000494:pharmacology
C513450:CDCA7L protein, human; D036341:Intercellular Signaling Peptides and Proteins; D046912:Multiprotein Complexes; D012097:Repressor Proteins; C119380:lens epithelium-derived growth factor; D019427:HIV Integrase; D015032:Zinc