The Eph Tyrosine Kinase Receptors EphB2 and EphA2 Are Novel Proteolytic Substrates of Tissue Factor/Coagulation Factor VIIa
2014 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 289, no 47Article in journal (Refereed) Published
Tissue factor (TF) binds the serine protease factor VIIa (FVIIa) to form a proteolytically active complex that can trigger coagulation or activate cell signaling. Here we addressed the involvement of tyrosine kinase receptors (RTKs) in TF/FVIIa signaling by antibody array analysis and subsequently found that EphB2 and EphA2 of the Eph RTK family were cleaved in their ectodomains by TF/FVIIa. We used N-terminal Edman sequencing and LC-MS/MS analysis to characterize the cleaved Eph isoforms and identified a key arginine residue at the cleavage site, in agreement with the tryptic serine protease activity of FVIIa. Protease-activated receptor 2 (PAR2) signaling and downstream coagulation activity was non-essential in this context, in further support of a direct cleavage by TF/FVIIa. EphB2 was cleaved by FVIIa concentrations in the subnanomolar range in a number of TF expressing cell types, indicating that the active cellular pool of TF was involved. FVIIa caused potentiation of cell repulsion by the EphB2 ligand ephrin-B1, demonstrating a novel proteolytical event to control Eph-mediated cell segregation. These results define Eph RTKs as novel proteolytical targets of TF/FVIIa and provide new insights into how TF/FVIIa regulates cellular functions independently of PAR2.
Place, publisher, year, edition, pages
2014. Vol. 289, no 47
Biochemistry and Molecular Biology
IdentifiersURN: urn:nbn:se:uu:diva-240089DOI: 10.1074/jbc.M114.599332ISI: 000345335000001PubMedID: 25281742OAI: oai:DiVA.org:uu-240089DiVA: diva2:775940