Cell surface glycoprotein serine protease that participates in extracellular matrix degradation and involved in many cellular processes including tissue remodeling, fibrosis, wound healing, inflammation and tumor growth. Both plasma membrane and soluble forms exhibit post-proline cleaving endopeptidase activity, with a marked preference for Ala/Ser-Gly-Pro-Ser/Asn/Ala consensus sequences, on substrate such as alpha-2-antiplasmin SERPINF2 and SPRY2 (PubMed:14751930, PubMed:16223769, PubMed:16480718, PubMed:16410248, PubMed:17381073, PubMed:18095711, PubMed:21288888, PubMed:24371721). Degrade also gelatin, heat-denatured type I collagen, but not native collagen type I and IV, vitronectin, tenascin, laminin, fibronectin, fibrin or casein (PubMed:9065413, PubMed:2172980, PubMed:7923219, PubMed:10347120, PubMed:10455171, PubMed:12376466, PubMed:16223769, PubMed:16651416, PubMed:18095711). Also has dipeptidyl peptidase activity, exhibiting the ability to hydrolyze the prolyl bond two residues from the N-terminus of synthetic dipeptide substrates provided that the penultimate residue is proline, with a preference for Ala-Pro, Ile-Pro, Gly-Pro, Arg-Pro and Pro-Pro (PubMed:10347120, PubMed:10593948, PubMed:16175601, PubMed:16223769, PubMed:16651416, PubMed:16410248, PubMed:17381073, PubMed:21314817, PubMed:24371721, PubMed:24717288). Natural neuropeptide hormones for dipeptidyl peptidase are the neuropeptide Y (NPY), peptide YY (PYY), substance P (TAC1) and brain natriuretic peptide 32 (NPPB) (PubMed:21314817). The plasma membrane form, in association with either DPP4, PLAUR or integrins, is involved in the pericellular proteolysis of the extracellular matrix (ECM), and hence promotes cell adhesion, migration and invasion through the ECM. Plays a role in tissue remodeling during development and wound healing. Participates in the cell invasiveness towards the ECM in malignant melanoma cancers. Enhances tumor growth progression by increasing angiogenesis, collagen fiber degradation and apoptosis and by reducing antitumor response of the immune system. Promotes glioma cell invasion through the brain parenchyma by degrading the proteoglycan brevican. Acts as a tumor suppressor in melanocytic cells through regulation of cell proliferation and survival in a serine protease activity-independent manner. Hydrolysis of Pro-|-Xaa >> Ala-|-Xaa in oligopeptides. Release of an N-terminal dipeptide, Xaa-Yaa-|-Zaa-, from a polypeptide, preferentially when Yaa is Pro, provided Zaa is neither Pro nor hydroxyproline. Gelatinase activity is inhibited by serine-protease inhibitors, such as phenylmethylsulfonyl fluoride (PMSF), 4-(2-aminoethyl)-benzenesulfonyl fluoride hydrochloride (AEBSF), 4-amidino phenylsulfonyl fluoride (APSF) and diisopropyl fluorophosphate (DFP), N-ethylmaleimide (NEM) and phenylmethylsulfonyl fluoride (PMSF). Dipeptidyl peptidase activity is inhibited by 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), diisopropylfluorophosphate (DFP). Prolyl endopeptidase activity is inhibited by the boronic acid peptide Ac-Gly-BoroPro, Ac-Gly-Pro-chloromethyl ketone and Thr-Ser-Gly-chloromethyl ketone. Optimum pH is 6-8.4 for gelatinase activity. At pH lower than 5 inhibited gelatinase activity. Optimum temperature is 37 degrees Celsius for gelatinase activity. Temperatures above 50 degrees Celsius inhibit gelatinase activity. Homodimer; homodimerization is required for activity of both plasma membrane and soluble forms. The monomer is inactive. Heterodimer with DPP4. Interacts with PLAUR; the interaction occurs at the cell surface of invadopodia membranes. Interacts with ITGB1. Interacts with ITGA3. Associates with integrin alpha-3/beta-1; the association occurs in a collagen-dependent manner at the cell surface of invadopodia membranes. Localized on cell surface with lamellipodia and invadopodia membranes and on shed vesicles. Colocalized with DPP4 at invadopodia and lamellipodia membranes of migratory activated endothelial cells in collagenous matrix. Colocalized with DPP4 on endothelial cells of capillary-like microvessels but not large vessels within invasive breast ductal carcinoma. Anchored and enriched preferentially by integrin alpha-3/beta-1 at invadopodia, plasma membrane protrusions that correspond to sites of cell invasion, in a collagen-dependent manner. Localized at plasma and ruffle membranes in a collagen-independent manner. Colocalized with PLAUR preferentially at the cell surface of invadopodia membranes in a cytoskeleton-, integrin- and vitronectin-dependent manner. Concentrated at invadopodia membranes, specialized protrusions of the ventral plasma membrane in a fibrobectin-dependent manner. Colocalizes with extracellular components (ECM), such as collagen fibers and fibronectin. Found in blood plasma and serum. Expressed in adipose tissue. Expressed in the dermal fibroblasts in the fetal skin. Expressed in the granulation tissue of healing wounds and on reactive stromal fibroblast in epithelial cancers. Expressed in activated fibroblast-like synoviocytes from inflamed synovial tissues. Expressed in activated hepatic stellate cells (HSC) and myofibroblasts from cirrhotic liver, but not detected in normal liver. Expressed in glioma cells (at protein level). Expressed in glioblastomas and glioma cells. Isoform 1 and isoform 2 are expressed in melanoma, carcinoma and fibroblast cell lines. In fibroblasts at times and sites of tissue remodeling during development, tissue repair and carcinogenesis. Up-regulated upon tumor stem cell differentiation. Up-regulated by transforming growth factor-beta, 12-O-tetradecanoyl phorbol-13-acetate and retinoids. N-glycosylated. The N-terminus may be blocked. Major isoform. Upstream open reading frames ORF(s)-containing region inhibits the translation of its downstream ORF. Belongs to the peptidase S9B family.