Characterization of a ligand for receptor protein-tyrosine kinase HTK expressed in immature hematopoietic cells.
Oncogene
; 13(4): 813-22, 1996 Aug 15.
Article
em En
| MEDLINE
| ID: mdl-8761303
ABSTRACT
HTK is a receptor tyrosine kinase that belongs to the Eph subfamily. An extensive screening using BIAcore system revealed that a colon cancer cell line, C-1, expressed the ligand for HTK. From the conditioned medium of C-1 cells, a soluble form of ligand was purified by receptor affinity chromatography, and the isolation of full-length cDNA revealed that this ligand is identical to the human HTK ligand (HTKL) previously reported. HTK receptor tyrosine phosphorylation was induced by membrane-bound or clustered soluble HTKL but not by unclustered soluble HTKL, indicating that HTKL requires cell-to-cell interaction for receptor activation. Binding analysis demonstrated that HTKL binds to HTK with a much higher affinity (Kd 1.23 nM) than the other transmembrane-type ligand for Eph family, LERK-2/ELKL (Kd 135 nM). The expression of HTK in cord blood cells was upregulated after the culture in the presence of stem cell factor. Clustered soluble HTKL stimulated the proliferation of sorted HTK+ cord blood cells and a hematopoietic cell line, UT-7/EPO from which HTK was isolated. These findings suggest the involvement of HTK-HTKL system in the proliferation of HTK+ hematopoietic progenitor cells in the hematopoietic environment.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Receptores Proteína Tirosina Quinases
/
Sangue Fetal
/
Proteínas de Membrana
Limite:
Humans
Idioma:
En
Revista:
Oncogene
Assunto da revista:
BIOLOGIA MOLECULAR
/
NEOPLASIAS
Ano de publicação:
1996
Tipo de documento:
Article
País de afiliação:
Japão