title: A bifunctional molecule that displays context-dependent cellular activity.
abstract: The cell-permeable dihydrofolate reductase inhibitor methotrexate was covalently linked to a ligand for the protein FKBP to create a bifunctional molecule called MTXSLF. The covalent tether between the two ligands was designed to be prohibitively short, so that unfavorable protein-protein interactions between DHFR and FKBP preclude formation of a trimeric complex. In vitro and in vivo experiments demonstrate that MTXSLF is an effective inhibitor of human DHFR, but that efficacy is decreased in the presence of human FKBP due to the high concentration of FKBP and its tight affinity for MTXSLF. MTXSLF also inhibits Plasmodium falciparum DHFR in vitro, but a low concentration of the weaker binding Plasmodium FKBP has no effect on the inhibitory potency of MTXSLF in vivo. These studies illustrate a potentially general strategy for modulating the biological activity of synthetic molecules that depends on the ligand-binding properties of a nontarget protein.
authors.affiliation: Department of Chemistry, Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Braun
authors.forename: Katherine T
authors.initials: KT
authors.lastname: Barglow
authors.forename: Yun-Ming
authors.initials: YM
authors.lastname: Lin
authors.forename: Thomas
authors.initials: T
authors.lastname: Akompong
authors.forename: Roger
authors.initials: R
authors.lastname: Briesewitz
authors.forename: Gregory T
authors.initials: GT
authors.lastname: Ray
authors.forename: Kasturi
authors.initials: K
authors.lastname: Haldar
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Wandless
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000962:Antimalarials / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D002460:Cell Line; D005260:Female; D005493:Folic Acid Antagonists / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008727:Methotrexate / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D008969:Molecular Sequence Data; D019696:Peptidylprolyl Isomerase; D010963:Plasmodium falciparum / Q000187:drug effects / Q000201:enzymology; D022021:Tacrolimus Binding Proteins / Q000737:chemistry / Q000378:metabolism; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism; D014599:Uterus / Q000166:cytology / Q000187:drug effects
chemical_list: D000962:Antimalarials; D005493:Folic Acid Antagonists; D008024:Ligands; D013762:Tetrahydrofolate Dehydrogenase; D022021:Tacrolimus Binding Proteins; C110054:FKBP10 protein, human; D019696:Peptidylprolyl Isomerase; D008727:Methotrexate