Renal cells activate the platelet receptor CLEC-2 through podoplanin.
We have recently shown that the C-type lectin-like receptor, CLEC-2, is expressed on platelets and that it mediates powerful platelet aggregation by the snake venom toxin rhodocytin. In addition, we have provided indirect evidence for an endogenous ligand for CLEC-2 in renal cells expressing HIV-1. This putative ligand facilitates transmission of HIV through its incorporation into the viral envelope and binding to CLEC-2 on platelets. The aim of the present study was to identify the ligand on these cells which binds to CLEC-2 on platelets. Recombinant CLEC-2 exhibits specific binding to HEK-293T (human embryonic kidney) cells in which the HIV can be grown. Furthermore, HEK-293T cells activate both platelets and CLEC-2-transfected DT-40 B-cells. The transmembrane protein podoplanin was identified on HEK-293T cells and was demonstrated to mediate both binding of HEK-293T cells to CLEC-2 and HEK-293T cell activation of CLEC-2-transfected DT-40 B-cells. Podoplanin is expressed on renal cells (podocytes). Furthermore, a direct interaction between CLEC-2 and podoplanin was confirmed using surface plasmon resonance and was shown to be independent of glycosylation of CLEC-2. The interaction has an affinity of 24.5+/-3.7 microM. The present study identifies podoplanin as a ligand for CLEC-2 on renal cells.
Christou
Charita M
CM
Henry Wellcome Building for Molecular Physiology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.
Pearce
Andrew C
AC
Watson
Aleksandra A
AA
Mistry
Anita R
AR
Pollitt
Alice Y
AY
Fenton-May
Angharad E
AE
Johnson
Louise A
LA
Jackson
David G
DG
Watson
Steve P
SP
O'Callaghan
Chris A
CA
D002460:Cell Line; D003001:Cloning, Molecular; D006031:Glycosylation; D006801:Humans; D007668:Kidney / Q000737:chemistry / Q000166:cytology*; D037181:Lectins, C-Type / Q000378:metabolism*; D008024:Ligands; D008562:Membrane Glycoproteins / Q000032:analysis / Q000378:metabolism*; D050199:Podocytes / Q000737:chemistry; D011485:Protein Binding; D020349:Surface Plasmon Resonance; D014162:Transfection; D000098853:Podoplanin
D037181:Lectins, C-Type; D008024:Ligands; D008562:Membrane Glycoproteins; C104778:CLEC2B protein, human; C117468:PDPN protein, human; D000098853:Podoplanin