The Fc receptor gamma-chain is necessary and sufficient to initiate signalling through glycoprotein VI in transfected cells by the snake C-type lectin, convulxin.
There is extensive evidence that FcR gamma-chain couples to the collagen receptor glycoprotein VI (GPVI) and becomes phosphorylated on tyrosines upon receptor cross-linking. However, it is not established whether this receptor complex is sufficient to initiate the signalling cascade. We transfected GPVI and the FcR gamma-chain into the human erythroleukaemia cell line K562, which lacks detectable expression of GPVI and the FcR gamma-chain. The results show that GPVI is unable to signal when expressed alone, despite its surface expression, upon stimulation with the snake C-type lectin, convulxin. Coexpression of the FcR gamma-chain confers signalling properties on the receptor. Furthermore, cotransfection of the FcR gamma-chain and two mutant versions of GPVI shows that the transmembrane arginine and cytoplasmic tail of GPVI are necessary for association with the FcR gamma-chain. These results demonstrate that reconstitution of the GPVI-FcR gamma-chain complex in cells expressing the necessary signalling network is sufficient to initiate signalling events in response to convulxin and collagen-related peptide.
Berlanga
Oscar
O
Department of Pharmacology, University of Oxford, UK. oscar.berlamga@pharm.ox.ac.uk
Tulasne
David
D
Bori
Teresa
T
Snell
Daniel C
DC
Miura
Yoshiki
Y
Jung
Stephanie
S
Moroi
Masaaki
M
Frampton
Jonathan
J
Watson
Steve P
SP
D000818:Animals; D001120:Arginine / Q000378:metabolism; D001665:Binding Sites; D019556:COS Cells / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002352:Carrier Proteins / Q000494:pharmacology*; D002522:Chlorocebus aethiops; D003094:Collagen / Q000494:pharmacology; D003435:Crotalid Venoms / Q000235:genetics / Q000494:pharmacology*; D004792:Enzyme Precursors / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D019169:Jurkat Cells / Q000378:metabolism; D020014:K562 Cells / Q000187:drug effects / Q000378:metabolism; D037181:Lectins, C-Type; D010455:Peptides; D010766:Phosphorylation; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011961:Receptors, Fc / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology; D000072377:Syk Kinase; D014162:Transfection; D014407:Tumor Cells, Cultured
D002352:Carrier Proteins; D003435:Crotalid Venoms; D004792:Enzyme Precursors; D047908:Intracellular Signaling Peptides and Proteins; D037181:Lectins, C-Type; D010455:Peptides; D010980:Platelet Membrane Glycoproteins; D011961:Receptors, Fc; C435908:collagen-related peptide; C098341:platelet membrane glycoprotein VI; C028890:convulxin; D003094:Collagen; D001120:Arginine; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; D002118:Calcium