| First Author | Briddon SJ | Year | 1999 |
| Journal | Blood | Volume | 93 |
| Issue | 11 | Pages | 3847-55 |
| PubMed ID | 10339492 | Mgi Jnum | J:55386 |
| Mgi Id | MGI:1337886 | Doi | 10.1182/blood.v93.11.3847.411k17_3847_3855 |
| Citation | Briddon SJ, et al. (1999) Collagen mediates changes in intracellular calcium in primary mouse megakaryocytes through syk-dependent and -independent pathways. Blood 93(11):3847-55 |
| abstractText | We have characterized changes in [Ca2+]i in primary mouse megakaryocytes in response to fibrillar collagen and in response to cross-linking of the collagen receptor, the integrin alpha2beta1. The response to collagen was markedly different from that seen to a triple helical collagen-related peptide (CRP), which signals via the tyrosine kinases p59(fyn) and p72(syk). This peptide binds to the collagen receptor glycoprotein VI (GPVI), but not to the integrin alpha2beta1. Collagen elicited a sustained increase in [Ca2+]i composed primarily of influx of extracellular Ca2+ with some Ca2+ release from internal stores. In contrast to CRP, this response was only partially (approximately 30%) inhibited by the src-family kinase inhibitor PP1 (10 micromol/L) or by microinjection of the tandem SH2 domains of p72(syk). Collagen also caused an increase in [Ca2+]i in megakaryocytes deficient in either p59(fyn) or p72(syk), although the response was reduced by approximately 40% in both cases: Cross-linking of the alpha2 integrin increased [Ca2+]i in these cells exclusively via Ca2+ influx. This response was reduced by approximately 50% after PP1 pretreatment, but was significantly increased in fyn-deficient megakaryocytes. Collagen therefore increases [Ca2+]i in mouse megakaryocytes via multiple receptors, including GPVI, which causes Ca2+ mobilization, and alpha2beta1, which stimulates a substantial influx of extracellular Ca2+. |
