title: Expression profiles of protein tyrosine kinase genes in human embryonic stem cells.
abstract: Complex signaling pathways operate in human embryonic stem cells (hESCs) and are coordinated to maintain self-renewal and stem cell characteristics in them. Protein tyrosine kinases (PTKs) participate in diverse signaling pathways in various types of cells. Because of their functions as key molecules in various cellular processes, PTKs are anticipated to have important roles also in hESCs. In this study, we investigated the roles of PTKs in undifferentiated and differentiated hESCs. To establish comprehensive PTK expression profiles in hESCs, we performed reverse transcriptase PCR using degenerate primers according to the conserved catalytic PTK motifs in both undifferentiated and differentiated hESCs. Here, we identified 42 different kinases in two hESC lines, including 5 non-receptor tyrosine kinases (RTKs), 24 RTKs, and 13 dual and other kinases, and compared the protein kinase expression profiles of hESCs and retinoic acid-treated hESCs. Significantly, up- and downregulated kinases in undifferentiated hESCs were confirmed by real-time PCR and western blotting. MAP3K3, ERBB2, FGFR4, and EPHB2 were predominantly upregulated, while CSF1R, TYRO3, SRC, and GSK3A were consistently downregulated in two hESC lines. Western blot analysis showed that the transcriptional levels of these kinases were consistent with the translational levels. The obstruction of upregulated kinases' activities using specific inhibitors disturbed the undifferentiated status and induced the differentiation of hESCs. Our results support the dynamic expression of PTKs during hESC maintenance and suggest that specific PTKs that are consistently up- and downregulated play important roles in the maintenance of stemness and the direction of differentiation of hESCs.
authors.affiliation: Korea Research Institute of Bioscience and Biotechnology (KRIBB), Center for Regenerative Medicine, Yuseong-Gu, Daejeon 305-806, South Korea.
authors.forename: Mi-Young
authors.initials: MY
authors.lastname: Son
authors.forename: Janghwan
authors.initials: J
authors.lastname: Kim
authors.forename: Hyo-Won
authors.initials: HW
authors.lastname: Han
authors.forename: Sun-Mi
authors.initials: SM
authors.lastname: Woo
authors.forename: Yee Sook
authors.initials: YS
authors.lastname: Cho
authors.forename: Yong-Kook
authors.initials: YK
authors.lastname: Kang
authors.forename: Yong-Mahn
authors.initials: YM
authors.lastname: Han
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D052160:Benzothiazoles / Q000494:pharmacology; D015153:Blotting, Western / Q000379:methods; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D017931:DNA Primers / Q000235:genetics; D053595:Embryonic Stem Cells / Q000187:drug effects / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D008969:Molecular Sequence Data; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D011743:Pyrimidines / Q000494:pharmacology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors; D017468:Receptors, Fibroblast Growth Factor / Q000037:antagonists & inhibitors; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D015398:Signal Transduction / Q000502:physiology*; D020032:Tyrphostins / Q000494:pharmacology
chemical_list: D052160:Benzothiazoles; D017931:DNA Primers; D011505:Protein-Tyrosine Kinases; D011743:Pyrimidines; D018719:Erb-b2 Receptor Tyrosine Kinases; D017468:Receptors, Fibroblast Growth Factor; D020032:Tyrphostins; C115711:PD 173074; C098214:tyrphostin AG825; C508053:ERBB2 protein, human