As a positive regulator of collagen fibrillogenesis, it is probably involved in the organization and remodeling of the extracellular matrix (By similarity). May positively regulate MAP-kinase activity in adipocytes, leading to enhanced adipocyte proliferation and reduced adipocyte differentiation. May also positively regulate NF-kappa-B activity in macrophages by promoting the phosphorylation and subsequent degradation of I-kappa-B-alpha (NFKBIA), leading to enhanced macrophage inflammatory responsiveness. Can act as a transcriptional repressor. Interacts with different types of collagen, including collagens I, III, and V (By similarity). Interacts with GNG5, NFKBIA, MAPK1, MAPK3 and PTEN. May interact with calmodulin. Interaction with MAPK1 may stimulate DNA-binding. Binds to DNA in vitro. Expressed in aorta. Highly expressed in quiescent cells. The F5/8 type C domain binds to different types of collagen, including collagens I, III, and V. Phosphorylated by MAPK1 in vitro. Belongs to the peptidase M14 family. Although related to peptidase M14 family, lacks the active site residues and zinc-binding sites, suggesting that it has no carboxypeptidase activity.