CD167a is a membrane type II receptor kinase, containing a factor VIII-like domain. At least five isoforms are generated through alternative splicing of the kinase domain of human DDR1 gene. These isoforms are named wtih suffixes a to e. CD167a is expressed on epithelial cells, keratinocytes, leukocytes, monocytes and has been reported to be overexpressed in some breast carcinomas. CD167a expression can be upregulated by p53. CD167a has been reported to interact with a variety of proteins including collagen type II alpha 1, collagen type III alpha 1, collagen type V alpha 2, collagen type XI alpha 1, phospholipase gamma 1, SHC, and the lipid-anchored docking protein FRS2. CD167a can be phosphorylated on Y513. Animal studies suggest that CD167a is involved in arterial wound healing.