Blood, Vol. 96 No. 1 (July 1), 2000:
pp. 145-148
The elusive factor Xa receptor: failure to detect transcripts that
correspond to the published sequence of EPR-1
Guido J. R. Zaman and
Edward M. Conway
From N.V. Organon, Research and Development, Oss, The Netherlands;
and Department of Medicine, Institute of Medical Science, University of
Toronto, Toronto, Canada.
The coagulation protease factor Xa induces cellular
responses implicated in cardiovascular and inflammatory disease.
Effector-cell protease receptor 1 (EPR-1) is a functionally
characterized receptor of factor Xa, and the EPR-1
complementary DNA (cDNA) was published. Remarkably, the cDNA encoding
an inhibitor of apoptosis, survivin, is reportedly identical to that of
EPR-1 except for a few nucleotide differences and its
orientation opposite to EPR-1. To isolate the EPR-1
cDNA and gene, we surveyed gene databases for expressed sequence tags
(ESTs) that could be derived from EPR-1. All ESTs with strong
homology to EPR-1/survivin were derived from survivin and could not encode EPR-1. By polymerase chain reaction and Southern blot hybridization, EPR-1 was not detectable in the human or
murine genome, but survivin was. Our data suggest that EPR-1 is
either highly cell-specific or the published EPR-1 cDNA
includes sequences from clones derived from survivin messenger
RNA. The means by which factor Xa mediates its cellular effects
requires further evaluation.
