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Nanoparticle Self-Assembly Directed by Antagonistic Kinase and Phosphatase Activities

Authors


  • G. v. M. and D.-H. M. contributed equally to this work. We gratefully acknowledge Drs. Barbara Imperiali, Bianca Scullimbrene, and Dora Cidalia Almeida-Carrico for helpful discussions and generously providing cysteine-labeled CRK SH2 plasmid. We thank Erkki Ruoslahti for helpful discussions and critical review of this work. Financial support from NIH (BRP: 1R01CA124427-01), NIH/NCI (U54 CA119349-01, U54 CA119335), Packard Fellowship (1999-1453A), Whitaker Foundation Graduate Fellowship (G. v. M.), and NSF Graduate Fellowship (G. v. M.).

Abstract

Superparamagnetic Fe3O4nanoparticles (NPs) are engineered to reversibly self-assemble in response to antagonistic enzyme inputs. Tyrosine kinase activity directs substrate-NPs and SH2 domain-NPs to coalesce via polyvalent SH2-phosphopeptide binding. Phosphatase antagonizes this process and directs NP dispersion. By coupling assembly to substrate phosphorylation, the kinase activity is imaged via quantitative T2 relaxation changes in MRI.

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