UCMA is a secreted cartilage-specific protein located in chromosome 2 that is predominantly expressed in resting chondrocytes. It is secreted into the extracellular matrix as an uncleaved precursor and shows the same restricted distribution pattern in cartilage as UCMA mRNA. This protein is proteolytically processed and contains tyrosine sulfates. It seems to be to be involved in the negative control of osteogenic differentiation of osteochondrogenic precursor cells in peripheral zones of foetal cartilage [1].

1: Ucma, a novel secreted cartilage-specific protein with implications in osteogenesis. Surmann-Schmitt C, Dietz U, Kireva T, Adam N, Park J, Tagariello A, Onnerfjord P, Heinegard D, Schlotzer-Schrehardt U, Deutzmann R, von der Mark K, Stock M; J Biol Chem. 2008;283:7082-7093. PMID:18156182