Identification of chicken embryo kinase 5, a developmentally regulated receptor-type tyrosine kinase of the Eph family.

AUTOR(ES)

Pasquale, E B

RESUMO

Chicken embryo kinase 5 (Cek5) is a transmembrane tyrosine kinase of the Eph family that was identified by screening a 10-d chicken embryo cDNA expression library with anti-phosphotyrosine antibodies. The extracellular region of Cek5 contains a cysteine rich N-terminal subdomain and a C-terminal subdomain mostly devoid of cysteines and comprising two repeats similar to fibronectin type III repeats. Immunoblotting experiments with anti-Cek5 polyclonal antibodies indicated that Cek5 is a membrane-associated 120-kDa protein containing intramolecular (but not intermolecular) disulfide bonds. Cek5 is already expressed in 2-d-old chicken embryos and is also expressed, at higher levels, later in development. In 10-d-old chicken embryos, Cek5 is expressed at substantial levels in nearly all the tissues examined, whereas in adult it is expressed predominantly in the brain. The expression of Cek5 in the brain gradually diminishes during embryonic development, whereas in the skeletal muscle of the thigh a sharp decrease in Cek5 expression was detected at the time of terminal muscle differentiation. Its wide tissue distribution throughout development and its sustained expression in adult brain suggest that Cek5 is an important component of signal transduction pathways, likely to interact with a widely distributed and important ligand, which is as yet unknown.

Documentos Relacionados

• The ltk gene encodes a novel receptor-type protein tyrosine kinase.
• Unique signal transduction of Eyk: constitutive stimulation of the JAK-STAT pathway by an oncogenic receptor-type tyrosine kinase.
• Protein tyrosine phosphatase receptor-type O (PTPRO) exhibits characteristics of a candidate tumor suppressor in human lung cancer
• Pleiotrophin signals increased tyrosine phosphorylation of β-catenin through inactivation of the intrinsic catalytic activity of the receptor-type protein tyrosine phosphatase β/ζ
• Increased abundance of the receptor-type protein-tyrosine phosphatase LAR accounts for the elevated insulin receptor dephosphorylating activity in adipose tissue of obese human subjects.