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Peptidyl-prolyl isomerase 1 (Pin1) preserves the phosphorylation state of tissue factor and prolongs its release within microvesicles

Ettelaie, Camille; Collier, Mary; Featherby, Sophie; Greenman, John; Maraveyas, Anthony

Abstract

© 2017 Elsevier B.V. The exposure and release of TF is regulated by post-translational modifications of its cytoplasmic domain. Here, the potential of Pin1 to interact with the cytoplasmic domain of TF, and the outcome on TF function was examined. MDA-MB-231 and transfected-primary endothelial cells were incubated with either Pin1 deactivator Juglone, or its control Plumbagin, as well as transfected with Pin1-specific or control siRNA. TF release into microvesicles following activation, and also phosphorylation and ubiquitination states of cellular-TF were then assessed. Furthermore, the ability of Pin1 to bind wild-type and mutant forms of overexpressed TF-tGFP was investigated by co-immunoprecipitation. Additionally, the ability of recombinant or cellular Pin1 to bind to peptides of the C-terminus of TF, synthesised in different phosphorylation states was examined by binding assays and spectroscopically. Finally, the influence of recombinant Pin1 on the ubiquitination and dephosphorylation of the TF-peptides was examined. Pre-incubation of Pin1 with Juglone but not Plumbagin, reduced TF release as microvesicles and was also achievable following transfection with Pin1-siRNA. This was concurrent with early ubiquitination and dephosphorylation of cellular TF at Ser253. Pin1 co-immunoprecipitated with overexpressed wild-type TF-tGFP but not Ser258 → Ala or Pro259 → Ala substituted mutants. Pin1 did interact with Ser258-phosphorylated and double-phosphorylated TF-peptides, with the former having higher affinity. Finally, recombinant Pin1 was capable of interfering with the ubiquitination and dephosphorylation of TF-derived peptides. In conclusion, Pin1 is a fast-acting enzyme which may be utili sed by cells to protect the phosphorylation state of TF in activated cells prolonging TF activity and release, and therefore ensuring adequate haemostasis.

Journal Article Type Article
Publication Date 2018-01
Journal BBA - Molecular cell research
Print ISSN 0167-4889
Electronic ISSN 1879-2596
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 1865
Issue 1
Pages 12-24
DOI https://doi.org/10.1016/j.bbamcr.2017.09.016
Keywords Tissue factor; Cytoplasmic domain; Prolyl-peptidyl cis/trans isomerase 1; Phosphorylation; Ubiquitination; Microvesicles
Publisher URL http://www.sciencedirect.com/science/article/pii/S0167488917302598?via%3Dihub

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