B61 is a ligand for the ECK receptor protein-tyrosine kinase

Bartley, Timothy D.; Hunt, R. W. G.; Welcher, Andrew A.; Boyle, William J.; Parker, Vann P.; Lindberg, Richard A.; Lu, Hsieng S.; Colombero, Anne; Elliott, Robin; Guthrie, Brenda; Holst, Paige L.; Skrine, James D.; Toso, Robert; Zhang, Ming; Fernandez, E Gonzalez; Trail, Geraldine; Varnum, Brian; Yarden, Yosef; Hunter, Tony; Fox, Gary M.

doi:10.1038/368558a0

Cited by 226 publications

(145 citation statements)

References 15 publications

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“…This attachment is either mediated by a transmembrane domain (Lerk2, Beckmann et al, 1994;ELF-2, Bergemann et al, 1995) or through a linkage to a GPI tail (B61, Bartley et al, 1994;Ehk1-L, Davis et al, 1994;Lerk4, Kozlosky et al, 1995;AL-1, Winslow et al, 1995;and Elf-1, Cheng and Flanagan, 1994). To test whether the detected MDK1 ligand in mouse embryos is attached to the cell surface via a GPI linkage, whole mouse embryos were treated with phosphatidylinositol-speci®c phospholipase C (PI ± PLC), incubated with MDK1-AP and stained for bound AP activity (Figure 3).…”

Section: Resultsmentioning

confidence: 99%

“…These studies together with the identi®cation of a number of ligands suggested a participation of eck/ eph related RTKs in a number of morphogenetic processes . For example, eck and its ligand B61 (Bartley et al, 1994), are involved in neuronal survival of rat spinal cord cultures (Magal et al, 1996) as well as in TNF-a induced angiogenesis . The identi®cation of RAGS as a repulsive axon guidance signal (Drescher et al, 1995) as well as the identi®cation of complementary gradients in receptor and ligand expression of Elf-1 and Mek-4 during the development of the topographic retinotectal projection map has led to the implication of the eck/eph subfamily of RTKs in axonal guidance.…”

Section: Introductionmentioning

confidence: 99%

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Identification of Elf-1 and B61 as high affinity ligands for the receptor tyrosine kinase MDK1

Ciossek

Ullrich

1997

Oncogene

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Mouse Developmental Kinase 1 (MDK1) is a receptor tyrosine kinase of the eck/eph subfamily expressed in a variety of tissues during early mouse embryogenesis. To obtain further insight into the function of MDK1, we determined identity and localisation of its physiological ligand(s). Staining whole embryos with fusion proteins between the extracellular domain of MDK1 and human secreted alkaline phosphatase revealed areas of high receptor binding in the caudal mesencephalon, the frontal neocortex and the limb buds. This staining was sensitive to treatment with phosphatidylinositol-speci®c phospholipase C. Using Scatchard analysis, high a nity binding of Elf-1 (1.7610 710 M) and B61 (2.2610 710 M) towards MDK1 could be demonstrated. However, the transmembrane ligand Lerk2 displayed no measurable a nity for MDK1. Elf-1 and B61 bind to the three full-length MDK1 isoforms with similar dissociation constants. Slightly lower a nities were observed for the two truncated receptors MDK1-T1 and MDK1-T2. The activation of MDK1 with Elf-1 or B61 leads to the rapid autophosphorylation of MDK1 as well as tyrosine phosphorylation of an unknown 62 kDa phosphoprotein in Rat1 cells. These ®ndings implicate MDK1 in patterning processes during early mouse embryogenesis and suggest MDK1 involvement in early organogenesis and midbrain development.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Identification of Elf-1 and B61 as high affinity ligands for the receptor tyrosine kinase MDK1

Ciossek

Ullrich

1997

Oncogene

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“…The binding of ligands to their cognate Eph receptors on apposing cell surfaces results in autophosphorylation of the Eph receptor on tyrosines in the intracellular domain (Bartley et al, 1994;Davis et al, 1994). This has also been demonstrated for EphB2 (formerly designated Cek5, Nuk, or Sek-3) (Eph Nomenclature Committee, 1997) upon binding of its ligand ephrin-B1 (formerly Cek5-L or LERK2) (Shao et al, 1994;Holash et al, 1997).…”

Section: Introductionmentioning

confidence: 88%

Complex formation between EphB2 and Src requires phosphorylation of tyrosine 611 in the EphB2 juxtamembrane region

et al. 1998

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The cellular components of the neuronal signaling pathways of Eph receptor tyrosine kinases are only beginning to be elucidated. Here we show that in vivo tyrosine phosphorylation sites of the Eph receptors EphA3, EphA4, and EphB2 in embryonic retina serve as binding sites for the Src-homology 2 (SH2) domain of Src kinase. Furthermore, tyrosine-phosphorylated EphB2 was detected in Src immunoprecipitates from transfected Cos cells, indicating that EphB2 and Src can physically associate. Interestingly, a form of Src with reduced electrophoretic mobility and increased tyrosine phosphorylation was detected in Cos cells expressing tyrosine-phosphorylated EphB2, suggesting a functional interaction between EphB2 and Src. Yeast two-hybrid analysis in conjunction with site-directed mutagenesis demonstrated that phosphorylated tyrosine 611 in the juxtamembrane region of EphB2 is crucial for the interaction with the SH2 domain of Src. In contrast, binding of the carboxy-terminal SH2 domain of phospholipase Cg was not abolished upon mutation of tyrosine 611 in EphB2. Phosphopeptide mapping of autophosphorylated full-length EphB2, and wild-type and tyrosine to phenylalanine mutants of the EphB2 cytoplasmic domain fused to LexA, showed tyrosine 611 in the sequence motif YEDP as a major site of autophosphorylation in EphB2. Our mutational analysis also indicated that tyrosines 605 and 611 are important for EphB2 kinase activity. We propose Src kinase as a downstream e ector that mediates the neuron's response to Eph receptor activation.

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“…Blood samples were collected on Day 18 following vector inoculation from four mice per group by the retro-orbital bleed under anesthesia to monitor the development of vector immunity by enzyme-linked immunosorbent assay (ELISA). Mice were killed with an overdose of an anesthetic when the tumors reached a volume of approximately 1000 mm 3 or on Day 48 postinoculation.…”

Section: Cell Viability Assaymentioning

confidence: 99%

“…1,2 In healthy breast epithelial cells, EphA2 is associated with one of its Ephrin ligands (A1-A5), predominantly 23 kDa EphrinA1. This binding leads to autophosphorylation of three tyrosine residues present in the intracytoplasmic domain of EphA2 [3][4][5][6] and then activates or inhibits other kinases before getting internalized and degraded. [7][8][9] Functionally altered EphA2 in invasive human breast cancer cells fails to bind to its ligand EphrinA1 leading to the accumulation of unphosphorylated EphA2.…”

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confidence: 99%

Immunocompetent mouse model of breast cancer for preclinical testing of EphA2-targeted therapy

et al. 2004

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EphA2, a receptor tyrosine kinase, is elevated in many invasive human breast cancers, and the majority of EphA2 remains unphosphorylated. The successful attachment of ligand EphrinA1 present on the surface of adjacent cells to EphA2 initiates EphA2 phosphorylation leading to its turnover. In vivo efficacy of various approaches targeting EphA2 for breast cancer therapy is usually evaluated in nude mice bearing human breast cancer xenografts. In order to establish an immunocompetent mouse model of breast cancer for EphA2-targeted therapies, we evaluated a mouse breast cancer cell line (MT1A2) for EphA2 expression and phosphorylation. Overexpression of EphA2 was observed in MT1A2 cells and the majority of it remained unphosphorylated signifying that EphA2 in MT1A2 cells behaved similar to that of human breast cancer cells. Human adenovirus subtype 5 (HAd5) vectors expressing secretory forms of EphrinA1 were used for in vitro and in vivo targeting of MT1A2-derived EphA2. MT1A2 cells infected with HAd-EphrinA1-Fc (HAd expressing extracellular domain of human EphrinA1 attached to Fc portion of human IgG1 heavy chain) induced EphA2 activation and its turnover. This led to inhibition in MT1A2 cell colony formation in soft agar and cell viability in monolayer culture. In addition, MT1A2 cells-infected with HAd-EphrinA1-Fc failed to form tumors in syngeneic FVB/n mice at least 32 days postinoculation. Moreover, intratumoral inoculation of FVB/n mice-bearing MT1A2-induced tumors with HAd-EphrinA1-Fc slowed the tumor growth and also resulted in the development of vector-specific immune response. These results indicate that FVB/n mice-bearing MT1A2-induced tumors could serve as an immunocompetent model of breast cancer for EphA2-targeted therapeutic strategies.

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B61 is a ligand for the ECK receptor protein-tyrosine kinase

Cited by 226 publications

References 15 publications

Identification of Elf-1 and B61 as high affinity ligands for the receptor tyrosine kinase MDK1

Identification of Elf-1 and B61 as high affinity ligands for the receptor tyrosine kinase MDK1

Complex formation between EphB2 and Src requires phosphorylation of tyrosine 611 in the EphB2 juxtamembrane region

Immunocompetent mouse model of breast cancer for preclinical testing of EphA2-targeted therapy

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