Plays an important role in the regulation of embryonic development, cell proliferation and cell differentiation, and is required for normal cardiomyocyte proliferation and heart development. Interacts with FGFR1 and FGFR2. In adult, predominantly expressed in heart, in the cardiac myocytes. Not detected in brain, lung, liver, kidney and white adipose tissue. In embryos, predominantly expressed in the brown adipose tissue. Expression in brown adipose tissue decreased greatly after birth. Belongs to the heparin-binding growth factors family.