TY - JOUR
T1 - Synthetic heterovalent inhibitors targeting recognition E3 components of the N-end rule pathway
AU - Min, Jae Lee
AU - Pal, Krishnendu
AU - Tasaki, Takafumi
AU - Roy, Sayantani
AU - Jiang, Yonghua
AU - Jee, Young An
AU - Banerjee, Rajkumar
AU - Yong, Tae Kwon
PY - 2008/1/8
Y1 - 2008/1/8
N2 - 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.
AB - 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.
KW - Cardiovascular cardiomyocyte
KW - N-recognin
KW - Protein degradation
KW - Ubiquitin
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U2 - 10.1073/pnas.0708465105
DO - 10.1073/pnas.0708465105
M3 - Article
C2 - 18162545
AN - SCOPUS:38349095024
SN - 0027-8424
VL - 105
SP - 100
EP - 105
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 1
ER -