Ig (immunoglobulin) superfamily members exhibit functional characteristics including immune responses, growth factor signaling and cell adhesion. IGSF10 (immunoglobulin superfamily, member 10), also known as Calvaria mechanical force protein 608 (CMF608), is a 2,623 amino acid secreted protein that contains an N-terminal signal peptide, six leucine-rich repeats (LRRs), and 12 immunoglobulin-like repeats. IGSF10 exists as multiple alternatively spliced isoforms, and is expressed in bone. Specifically, expression of IGSF10 is limited to mesenchymal osteochondroprogenitors with fibroblast-like morphology, where it is thought to be involved in the maintenance of the osteochondroprogenitor cells pool and its down-regulation precedes terminal differentiation.