Comparison of CLEC-2 and GPVI signaling in platelets: the role of adaptor proteins

Hughes, Craig Edward (2010). Comparison of CLEC-2 and GPVI signaling in platelets: the role of adaptor proteins. University of Birmingham. Ph.D.

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Abstract

GPVI activates platelets through an ITAM pathway by activation of Src and Syk kinases leading to activation of PLC\(_y\)2. CLEC-2 has been shown to activate platelets using an ITAM-like sequence in its cytoplasmic tail that is also dependent on Src and Syk kinases, but shows a partial rather than an absolute dependence on adapter SLP-76 for activation of PLC\(_y\)2. The aim of this thesis is to understand some of the key differences in these signalling pathways. GPVI is in complex with FcRwhich contains the ITAM sequence (Yxx(L/I)x\(_{6-12}\)Yxx(L/I)). These two tyrosines provide a docking site for the tandem-SH2 domains of Syk. In this thesis I show that CLEC-2 signalling through Syk is mediated by phosphorylation of the CLEC-2 YxxL sequence, receptor dimerisation and cross-linking by the Syk SH2 domains. I also show that the differential requirement for SLP-76 is not mediated by Gads. Both signalling pathways also show partial dependency for LAT. I also show that a novel protein, G6f, is not able to substitute for LAT in this signalling pathway and also exclude the LAT-family proteins PAG, LIME, LAX and NTAL as potential LAT replacements in platelet activation by GPVI. These results extend our understanding of platelet activation by CLEC-2.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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