[Isoform 1]: Acts as a transcriptional repressor (PubMed:17974029). Has mitogenic activity for fibroblasts (PubMed:11751870, PubMed:26845719). Heparin-binding protein (PubMed:15491618). {ECO:0000269|PubMed:11751870, ECO:0000269|PubMed:15491618, ECO:0000269|PubMed:17974029, ECO:0000269|PubMed:26845719}. [Isoform 2]: Does not have mitogenic activity for fibroblasts (PubMed:26845719). Does not bind heparin (PubMed:26845719). . [Isoform 3]: Has mitogenic activity for fibroblasts (PubMed:26845719). Heparin-binding protein (PubMed:26845719). . This is the function of ENSG00000143321 (HDGF, heparin binding growth factor).