Enables collagen binding activity and protein N-terminus binding activity. Involved in several processes, including animal organ development; response to lipopolysaccharide; and wound healing. Located in extracellular matrix. Part of collagen type VI trimer. Biomarker of asthma; myocardial infarction; and obesity. Human ortholog(s) of this gene implicated in breast carcinoma; congenital stromal corneal dystrophy; and high grade glioma. Orthologous to human DCN (decorin). [provided by Alliance of Genome Resources, Apr 2022]