Synthetic heterovalent inhibitors targeting recognition E3 components of the N-end rule pathway

Jae Lee Min, Krishnendu Pal, Takafumi Tasaki, Sayantani Roy, Yonghua Jiang, Young An Jee, Rajkumar Banerjee, Tae Kwon Yong

Research output: Contribution to journalArticlepeer-review


Multivalent binding allows high selectivity and affinity in a ligand-protein interaction. The N-end rule pathway is a ubiquitin (Ub)-dependent proteolytic system in which specific E3s, called N-recognins, mediate ubiquitylation through the recognition of types 1 and 2, destabilizing N-terminal residues of substrates. We recently identified a set of E3 Ub ligases (named UBR1-UBR7) containing the 70-residue UBR box, and we demonstrated that UBR1, UBR2, UBR4, and UBR5 can bind to destabilizing N-terminal residues. To explore a model of heterovalent interaction to the N-recognin family, we synthesized the small-molecule compound RF-C11, which bears two heterovalent ligands designed to target N-recognins, together with control molecules with two homovalent ligands. We demonstrate that heterovalent ligands of RF-C11 selectively and cooperatively bind cognate-binding sites of multiple N-recognins and thereby inhibit both types 1 and 2 N-end rule activities. Furthermore, the efficacy of heterovalent RF-C11 was substantially higher than homovalent inhibitors, which can target either a type 1 or type 2 site, providing the molecular basis of designing multivalent inhibitors for the control of specific intracellular pathways. In addition, RF-C11 exhibited higher efficacy and stability, compared with dipeptides bearing destabilizing N-terminal residues, which are known competitive inhibitors of the pathway. We also used the heterovalent compound to study the function of N-recognins in cardiac signaling. Using mouse and rat cardiomyocytes, we demonstrate that the N-end rule pathway has a cell-autonomous function in cardiac proliferation and hypertrophy, explaining our earlier results implicating the pathway in cardiac development and proteolysis of multiple cardiovascular regulators.

Original languageEnglish (US)
Pages (from-to)100-105
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number1
StatePublished - Jan 8 2008


  • Cardiovascular cardiomyocyte
  • N-recognin
  • Protein degradation
  • Ubiquitin

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Synthetic heterovalent inhibitors targeting recognition E3 components of the N-end rule pathway'. Together they form a unique fingerprint.

Cite this