Platelet receptor Gi24, also known as B7-H5 and stress-induced secreted protein-1 (Sisp-1), is a protein that in humans is encoded by the C10orf54 gene, which contains 1 Ig-like (immunoglobulin-like) domain. As for C10orf54 gene, C10orf54 appears to positively interact with BMP-4, potentiating BMP signaling and the transition from an undifferentiated to a differentiated state on ESCs. Human C10orf54 undergoes proteolytic cleavage by MT1-MMP, generating a soluble 30 kDa extracellular fragment plus a 25-30 kDa membrane-bound fragment.