title: Tyrosine kinase BMX phosphorylates phosphotyrosine-primed motif mediating the activation of multiple receptor tyrosine kinases.
abstract: The nonreceptor tyrosine kinase BMX (bone marrow tyrosine kinase gene on chromosome X) is abundant in various cell types and activated downstream of phosphatidylinositol-3 kinase (PI3K) and the kinase Src, but its substrates are unknown. Positional scanning peptide library screening revealed a marked preference for a priming phosphorylated tyrosine (pY) in the -1 position, indicating that BMX substrates may include multiple tyrosine kinases that are fully activated by pYpY sites in the kinase domain. BMX phosphorylated focal adhesion kinase (FAK) at Tyr⁵⁷⁷ subsequent to its Src-mediated phosphorylation at Tyr⁵⁷⁶. Loss of BMX by RNA interference or by genetic deletion in mouse embryonic fibroblasts (MEFs) markedly impaired FAK activity. Phosphorylation of the insulin receptor in the kinase domain at Tyr¹¹⁸⁹ and Tyr¹¹⁹⁰, as well as Tyr¹¹⁸⁵, and downstream phosphorylation of the kinase AKT at Thr³⁰⁸ were similarly impaired by BMX deficiency. However, insulin-induced phosphorylation of AKT at Ser⁴⁷³ was not impaired in Bmx knockout MEFs or liver tissue from Bmx knockout mice, which also showed increased insulin-stimulated glucose uptake, possibly because of decreased abundance of the phosphatase PHLPP (PH domain leucine-rich repeat protein phosphatase). Thus, by identifying the pYpY motif as a substrate for BMX, our findings suggest that BMX functions as a central regulator among multiple signaling pathways mediated by tyrosine kinases.
authors.affiliation: Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Sen
authors.initials: S
authors.lastname: Chen
authors.affiliation: Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Xinnong
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Signal Transduction Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Christina A
authors.initials: CA
authors.lastname: Gewinner
authors.affiliation: Signal Transduction Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Asara
authors.affiliation: Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Nicholas I
authors.initials: NI
authors.lastname: Simon
authors.affiliation: Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Changmeng
authors.initials: C
authors.lastname: Cai
authors.affiliation: Signal Transduction Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.|Weill Cornell Medical College and New York Presbyterian Hospital, New York, NY 10065, USA.
authors.forename: Lewis C
authors.initials: LC
authors.lastname: Cantley
authors.affiliation: Hematology-Oncology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Balk
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid; D004789:Enzyme Activation / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D015151:Immunoblotting; D051379:Mice; D018345:Mice, Knockout; D019151:Peptide Library; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D011972:Receptor, Insulin / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D053719:Tandem Mass Spectrometry
chemical_list: D019151:Peptide Library; D019000:Phosphotyrosine; C492366:Bmx protein, mouse; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; D011972:Receptor, Insulin; D051416:Focal Adhesion Protein-Tyrosine Kinases