The CD34 family of cell surface transmembrane proteins includes the hematopoietic progenitor cell antigen CD34, Podocalyxin, and Endoglycan. This single-pass sialomucin‑like transmembrane protein is heavily glycosylated and phosphorylated by Protein kinase C (PKC). CD34 is a 115 kDa glycoprotein found on multipotent precursors, bone marrow stromal cells, embryonic fibroblasts, vascular endothelia, as well as some populations of mesenchymal stem cells, and tumor cell lines. CD34 is involved in the adhesion of stem cells to the bone marrow extracellular matrix or to stromal cells.
