title: Changing the subcellular location of the oncoprotein Bcr-Abl using rationally designed capture motifs.
abstract: OBJECTIVE
  Bcr-Abl, the causative agent of chronic myelogenous leukemia (CML), localizes in the cytoplasm where its oncogenic signaling leads to proliferation of cells. If forced into the nucleus Bcr-Abl causes apoptosis. To achieve nuclear translocation, binding domains for capture of Bcr-Abl were generated and attached to proteins with signals destined for the nucleus. These resulting proteins would be capable of binding and translocating endogenous Bcr-Abl to the nucleus.
  
  
  METHODS
  Bcr-Abl was targeted at 3 distinct domains for capture: by construction of high affinity intracellular antibody domains (iDabs) to regions of Bcr-Abl known to promote cytoplasmic retention, via its coiled coil domain (CC), and through a naturally occurring protein-protein interaction domain (RIN1). These binding domains were then tested for their ability to escort Bcr-Abl into the nucleus using a "protein switch" or attachment of 4 nuclear localization signals (NLSs).
  
  
  RESULTS
  Although RIN1, ABI7-iDab, and CCmut3 constructs all produced similar colocalization with Bcr-Abl, only 4NLS-CCmut3 produced efficient nuclear translocation of Bcr-Abl.
  
  
  CONCLUSIONS
  We demonstrate that a small binding domain can be used to control the subcellular localization of Bcr-Abl, which may have implications for CML therapy. Our ultimate future goal is to change the location of critical proteins to alter their function.
authors.affiliation: Department of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, University of Utah, 421 Wakara Way, Rm. 318, Salt Lake City, Utah 84108, USA.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Dixon
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Constance
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Terence H
authors.initials: TH
authors.lastname: Rabbitts
authors.forename: Carol S
authors.initials: CS
authors.lastname: Lim
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001665:Binding Sites; D019556:COS Cells; D048708:Cell Growth Processes / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000378:metabolism*; D016044:Fusion Proteins, bcr-abl / Q000378:metabolism*; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000378:metabolism; D051379:Mice; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D015398:Signal Transduction / Q000502:physiology
chemical_list: D016044:Fusion Proteins, bcr-abl