Eosinophil cationic protein

4A2O, 4X08, 1DYT, 4OXB, 2LVZ, 2KB5, 4OXF, 1QMT, 4OWZ, 1H1H, 4A2Y6037n/aENSG00000169397n/aP12724n/aNM_002935n/aNP_002926n/aEosinophil cationic protein (ECP) also known as ribonuclease 3 is a basic protein located in the eosinophil primary matrix. In humans, the eosinophil cationic protein is encoded by the RNASE3 gene.1dyt: X-RAY CRYSTAL STRUCTURE OF ECP (RNASE 3) AT 1.75 A1h1h: CRYSTAL STRUCTURE OF EOSINOPHIL CATIONIC PROTEIN IN COMPLEX WITH 2',5'-ADP AT 2.0 A RESOLUTION REVEALS THE DETAILS OF THE RIBONUCLEOLYTIC ACTIVE SITE1qmt: RECOMBINANT HUMAN EOSINOPHIL CATIONIC PROTEIN Eosinophil cationic protein (ECP) also known as ribonuclease 3 is a basic protein located in the eosinophil primary matrix. In humans, the eosinophil cationic protein is encoded by the RNASE3 gene. ECP is released during degranulation of eosinophils. This protein is related to inflammation and asthma because in these cases, there are increased levels of ECP in the body.There are three glycosolated forms of ECP and consequently ECP has a range of molecular weights from 18-22 kDa. Eosinophil cationic protein and the sequence related eosinophil-derived neurotoxin (RNASE2) are both members of the ribonuclease a superfamily. Both proteins possess neurotoxic, helmintho-toxic, and ribonucleo-lytic activities. Eosinophil cationic protein is localized to the granule matrix of the eosinophil. The ribonuclease activity of ECP is not essential for cytotoxicity. When the two known ribonuclease active-site residues are modified to non-functional counterparts (Lysine at position 38 to Arginine and Histidine at position 128 to Aspartate) and compared to the wild-type ECP, the mutated ECP retains its cytotoxicity but no longer has its ribonuclease activity. The experiment confirmed that converting the two amino acids to non-functional counterparts did inhibit ECP’s ribonuclease activity. However, ECP retained its anti-parasitic activity. Also, it did not change the production and transportation of ECP in bacteria. ECP is a potent cytotoxic protein capable of killing cells of guinea pig tracheal epithelium, mammalian leukemia, epidermis carcinoma, and breast carcinoma, as well as non-mammalian cells such as parasites, bacteria, and viruses. Mature ECP is cytotoxic to human bronchial epithelial (BEAS-2B) cells by specific binding to cell surface heparan sulfate proteoglycans (HSPGs) followed by endocytosis. Studies show that ECP, along with other RNases including EDN, had been reported to induce apoptosis in cells. A latest study indicated that ECP caused cytotoxicity in HL-60 and HeLa cells via caspase-3 like activity. Accordingly, cytotoxic RNases play an important role in cell death. However, the mechanism of ECP-induced apoptosis is still not fully verified. Recent studies have shown that eosinophils can induce epithelial cell death via apoptosis and necrosis. ECP triggers apoptosis by caspase-8 activation through mitochondria-independent pathway. Increases in chromatin condensation, sub-G1 population, PARP cleavage, and DNA fragmentation indicate that ECP induces apoptosis in human bronchial epithelial (BEAS-2B) cells.