DEP-1 (density enhanced protein tyrosine phosphatase-1), also known as CD148, HPTP-eta, and PTP receptor type J (PTPRJ), is an enzyme that removes phosphate groups covalently attached to tyrosine residues in proteins. DEP-1 is a large glycoprotein expressed on the cell surface at levels that increase with high cell density. DEP-1 is widely expressed in tissues, particularly those forming epithelioid monolayers. In the immune system, DEP-1 is found on all cell lineages with highest expression levels on granulocytes.