描述:
EphB4, also known as Htk, Myk1, Tyro11, and Mdk2, is a member of the Eph receptor tyrosine
kinase family and binds EphrinB2. The A and B class Eph proteins have a common structural
organization. The human EphB4 cDNA encodes a 987 amino acid precursor that includes a 15
amino acid (aa) signal sequence, a 524aa extracellular domain (ECD), a 21 aa transmembrane
segment, and a 427 aa cytoplasmic domain. The ECD contains an Nterminal globular domain,
a cysteinerich domain, and two fibronectin type III domains. The cytoplasmic domain contains a
juxtamembrane motif with two tyrosine residues which are the major autophosphorylation sites,
a kinase domain, and a conserved sterile alpha motif (SAM). Activation of kinase activity occurs
after membranebound or clustered ligand recognition and binding. The ECD of human EphB4
shares 89% aa sequence identity with mouse EphB4 and 42 -45% aa sequence identity with
human EphB1, 2, and 3. EphB4 is expressed preferentially on venous endothelial cells (EC) and
inhibits cellcell adhesion, chemotaxis, and angiogenesis. Opposing effects are induced by
signaling through Ephrin-B2 expressed on arterial EC: adhesion, endothelial cell migration, and
vessel sprouting. EphB4 singaling contributes to new vascularization by guiding venous EC away
from EphrinB2 expressing EC. Ephrin-B2 signaling induces arterial EC to migrate towards
nascent EphB4 expressing vessels . The combination of forward signaling through EphB4 and
reverse signaling through EphrinB2 promotes in vivo mammary tumor growth and tumor-
associated angiogenesis. EphB4 promotes the differentiation of megakaryocytic and erythroid
progenitors but not granulocytic or monocytic progenitors.
原厂资料:
EphB4, also known as Htk, Myk1, Tyro11, and Mdk2, is a member of the Eph receptor tyrosine
kinase family and binds EphrinB2. The A and B class Eph proteins have a common structural
organization. The human EphB4 cDNA encodes a 987 amino acid precursor that includes a 15
amino acid (aa) signal sequence, a 524aa extracellular domain (ECD), a 21 aa transmembrane
segment, and a 427 aa cytoplasmic domain. The ECD contains an Nterminal globular domain,
a cysteinerich domain, and two fibronectin type III domains. The cytoplasmic domain contains a
juxtamembrane motif with two tyrosine residues which are the major autophosphorylation sites,
a kinase domain, and a conserved sterile alpha motif (SAM). Activation of kinase activity occurs
after membranebound or clustered ligand recognition and binding. The ECD of human EphB4
shares 89% aa sequence identity with mouse EphB4 and 42 -45% aa sequence identity with
human EphB1, 2, and 3. EphB4 is expressed preferentially on venous endothelial cells (EC) and
inhibits cellcell adhesion, chemotaxis, and angiogenesis. Opposing effects are induced by
signaling through Ephrin-B2 expressed on arterial EC: adhesion, endothelial cell migration, and
vessel sprouting. EphB4 singaling contributes to new vascularization by guiding venous EC away
from EphrinB2 expressing EC. Ephrin-B2 signaling induces arterial EC to migrate towards
nascent EphB4 expressing vessels . The combination of forward signaling through EphB4 and
reverse signaling through EphrinB2 promotes in vivo mammary tumor growth and tumor-
associated angiogenesis. EphB4 promotes the differentiation of megakaryocytic and erythroid
progenitors but not granulocytic or monocytic progenitors.