Lens epithelium-derived growth factor/p75 (LEDGF/p75, or PSIP1) is a transcriptional coactivator that tethers other proteins to gene bodies. The chromatin tethering function of LEDGF/p75 is hijacked by HIV integrase to ensure viral integration at sites of active transcription. LEDGF/p75 is also important for the development of mixed-lineage leukemia (MLL), where it tethers the MLL1 fusion complex at aberrant MLL targets, inducing malignant transformation. However, little is known about how the LEDGF/p75 protein interaction network is regulated. Here, we obtained solution structures of the complete interfaces between the LEDGF/p75 integrase binding domain (IBD) and its cellular binding partners and validated another binding partner, Mediator subunit 1 (MED1). We reveal that structurally conserved IBD-binding motifs (IBMs) on known LEDGF/p75 binding partners can be regulated by phosphorylation, permitting switching between low- and high-affinity states. Finally, we show that elimination of IBM phosphorylation sites on MLL1 disrupts the oncogenic potential of primary MLL1-rearranged leukemic cells. Our results demonstrate that kinase-dependent phosphorylation of MLL1 represents a previously unknown oncogenic dependency that may be harnessed in the treatment of MLL-rearranged leukemia.

• MeSH
• adaptorové proteiny signální transdukční genetika   metabolismus   MeSH
• aminokyselinové motivy MeSH
• fosforylace genetika   MeSH
• histonlysin-N-methyltransferasa genetika   metabolismus   MeSH
• HIV-integrasa genetika   metabolismus   MeSH
• HIV enzymologie   genetika   MeSH
• lidé MeSH
• mediátorový komplex - podjednotka 1 genetika   metabolismus   MeSH
• nádorové buněčné linie MeSH
• protoonkogenní protein MLL genetika   metabolismus   MeSH
• transkripční faktory genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Lens epithelium-derived growth factor (LEDGF/p75) is an epigenetic reader and attractive therapeutic target involved in HIV integration and the development of mixed lineage leukaemia (MLL1) fusion-driven leukaemia. Besides HIV integrase and the MLL1-menin complex, LEDGF/p75 interacts with various cellular proteins via its integrase binding domain (IBD). Here we present structural characterization of IBD interactions with transcriptional repressor JPO2 and domesticated transposase PogZ, and show that the PogZ interaction is nearly identical to the interaction of LEDGF/p75 with MLL1. The interaction with the IBD is maintained by an intrinsically disordered IBD-binding motif (IBM) common to all known cellular partners of LEDGF/p75. In addition, based on IBM conservation, we identify and validate IWS1 as a novel LEDGF/p75 interaction partner. Our results also reveal how HIV integrase efficiently displaces cellular binding partners from LEDGF/p75. Finally, the similar binding modes of LEDGF/p75 interaction partners represent a new challenge for the development of selective interaction inhibitors.

• MeSH
• dimerizace MeSH
• Escherichia coli MeSH
• histonlysin-N-methyltransferasa metabolismus   MeSH
• HIV-integrasa metabolismus   MeSH
• konsenzuální sekvence MeSH
• Lentivirus enzymologie   MeSH
• lidé MeSH
• mezibuněčné signální peptidy a proteiny metabolismus   MeSH
• molekulární sekvence - údaje MeSH
• proteiny metabolismus   MeSH
• protoonkogenní protein MLL metabolismus   MeSH
• represorové proteiny metabolismus   MeSH
• sekvence aminokyselin MeSH
• terciární struktura proteinů MeSH
• transposasy metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH