title: PTK6 Localized at the Plasma Membrane Promotes Cell Proliferation and MigratiOn Through Phosphorylation of Eps8.
abstract: Protein tyrosine kinase 6 (PTK6; also known as Brk) is closely related to the Src family kinases, but lacks a membrane-targeting myristoylation signal. Sublocalization of PTK6 at the plasma membrane enhances its oncogenic potential. To understand the mechanism(s) underlying the oncogenic property of plasma---membrane-associated PTK6, proteins phosphorylated by membrane-targeted myristoylated PTK6 (Myr-PTK6) were enriched and analyzed using a proteomics approach. Eps8 which was identified by this method is phosphorylated by Myr-PTK6 in HEK293 cells. Mouse Eps8 expressed in HEK293 cells is phosphorylated by Myr-PTK6 at residues Tyr497, Tyr524, and Tyr534. Compared to wild-type Eps8 (Eps8 WT), the phosphorylation-defective 3YF mutant (Eps8 3YF) reverts the increased proliferation, migration, and phosphorylation of ERK and FAK mediated by Eps8 WT in HEK293 cells overexpressing PTK6. PTK6 knockdown in T-47D breast cancer cells decreased EGF-induced phosphorylation of Eps8. Endogenous PTK6 phosphorylates ectopically expressed Eps8 WT, but not Eps8 3YF mutant, in EGF-stimulated T-47D cells. The EGF-induced Eps8 phosphorylation enhances activation of ERK and FAK, cell adhesion, and anchorage-independent colony formation in T-47D cells, but not in the PTK6-knokdown T-47D cells. These results indicate that plasma-membrane-associated PTK6 phosphorylates Eps8, which promotes cell proliferation, adhesion, and migration and, thus, tumorigenesis. J. Cell. Biochem. 118: 2887-2895, 2017. © 2017 Wiley Periodicals, Inc.
authors.affiliation: Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
authors.forename: Won-Sik
authors.initials: WS
authors.lastname: Shin
authors.affiliation: Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
authors.forename: Hyun Jae
authors.initials: HJ
authors.lastname: Shim
authors.affiliation: Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
authors.forename: Young Hun
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
authors.forename: Minju
authors.initials: M
authors.lastname: Pyo
authors.affiliation: Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
authors.forename: Jun Sang
authors.initials: JS
authors.lastname: Park
authors.affiliation: Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
authors.forename: So Yun
authors.initials: SY
authors.lastname: Ahn
authors.affiliation: Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
authors.forename: Seung-Taek
authors.identifier: 0000-0001-7300-9784
authors.initials: ST
authors.lastname: Lee
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D019943:Amino Acid Substitution; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement; D049109:Cell Proliferation; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D020125:Mutation, Missense; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000235:genetics; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C489989:EPS8 protein, human; D009363:Neoplasm Proteins; D011505:Protein-Tyrosine Kinases; C088375:PTK6 protein, human
keywords: EPS8; MIGRATION; PROLIFERATION; PTK6; TUMORIGENESIS