Angiogenin is a member of the ribonuclease superfamily with approximately 35% amino acid sequence identity with pancreatic RNase. Like other members of the ribonuclease superfamily, angiogenin is a cytotoxic agent that can eliminate cellular protein synthesis. Angiogenin causes inhibition of protein synthesis by functioning as a cytotoxic tRNA-specific RNase. Angiogenesis is the formation of blood vessels or capillaries from existing blood vessels due to specific signals. Angiogenin induces the growth of new blood vessels. It stimulates capillary and umbilical vein endothelial cells to produce diacylglycerol and secrete prostacyclin by phospholipase activation. Angiogenin exhibits both angiogenic and non-angiogenic activities and is involved in endothelial cell migration, proliferation, and differentiation. It is produced by a variety of tumor and normal cell types. Cells that express angiogenin include vascular endothelial and smooth muscle cells, fibroblasts, normal colonic epithelium, normal peripheral blood lymphocytes, lung and colonic epithelial tumor cell lines, and primary gastrointestinal adenocarcinomas. Angiogenin is also present in normal human plasma.

Nuclear and Secreted