Blood Platelets Express High Levels of the Pp60c-src-specific Tyrosine Kinase Activity
Overview
Authors
Affiliations
We have examined human and rabbit blood platelets for expression of pp60c-src, the normal cellular homolog of the transforming protein of Rous sarcoma virus. pp60c-src kinase activity was determined by an immune-complex kinase assay that uses enolase as the substrate, and pp60c-src protein levels were determined by an immunoblot assay. Lysates from platelets expressed high levels of pp60c-src-specific kinase activity and pp60c-src protein compared to the levels found in other tissues. pp60c-src was also found to be one of the major proteins phosphorylated in vitro in membranes isolated from platelets. Multiple protein species other than pp60c-src were also phosphorylated on tyrosine in the membrane phosphorylation reactions, and phosphotyrosine represented approximately equal to 80% of the total phosphoamino acid residues phosphorylated in the membranes. These results indicate that tyrosine kinases represent the major protein phosphorylating enzymes detected in isolated platelet membranes. Although the association of tyrosine kinase activity with many viral oncogene products and cellular growth hormone receptors has suggested a role for these enzymes in the regulation of cell proliferation, these results indicate that the expression of high levels of tyrosine kinase activity is not exclusively associated with proliferating cells.
Platelet Src family kinases: A tale of reversible phosphorylation.
Senis Y, Nagy Z, Mori J, Lane S, Lane P Res Pract Thromb Haemost. 2021; 5(3):376-389.
PMID: 33870023 PMC: 8035799. DOI: 10.1002/rth2.12495.
The (Patho)Biology of SRC Kinase in Platelets and Megakaryocytes.
De Kock L, Freson K Medicina (Kaunas). 2020; 56(12).
PMID: 33255186 PMC: 7759910. DOI: 10.3390/medicina56120633.
Maintenance of murine platelet homeostasis by the kinase Csk and phosphatase CD148.
Mori J, Nagy Z, Di Nunzio G, Smith C, Geer M, Ghaithi R Blood. 2018; 131(10):1122-1144.
PMID: 29301754 PMC: 5888341. DOI: 10.1182/blood-2017-02-768077.
Furukawa K, Fuse I, Iwakura Y, Sotoyama H, Hanyu O, Nawa H Cardiovasc Diabetol. 2017; 16(1):20.
PMID: 28178976 PMC: 5299653. DOI: 10.1186/s12933-017-0505-y.
Turro E, Greene D, Wijgaerts A, Thys C, Lentaigne C, Bariana T Sci Transl Med. 2016; 8(328):328ra30.
PMID: 26936507 PMC: 5903547. DOI: 10.1126/scitranslmed.aad7666.