| Modification Notes |
Hyaluronidases (HAases or HYALs) are a family of lysosomal enzymes that are crucial for the spread of bacterial infections and of toxins present in a variety of venoms. HYALs may also be involved in the progression of cancer. In humans, six HYAL proteins have been identified. HYAL proteins use hydrolysis to degrade hyaluronic acid (HA), which is present in body fluids, tissues and the extracellular matrix of vertebrate tissues. HA keeps tissues hydrated, maintains osmotic balance and promotes cell proliferation, differentiation and metastasis. HA is also an important structural component of cartilage and other tissues and acts as a lubricant in joints. HYAL2 is a 452 amino acid peptide that localizes to the lysosomes of mammalian cells. The hyaluronidase activity of HYAL2 is most efficient at a pH below 4, and it only hydrolyzes HAs of high molecular mass. HYAL2 is also the receptor for two exogenous oncogenic viruses, Jaagsiekte sheep retrovirus (JSRV) and Enzootic nasal tumor virus. The viral envelope of JSRV physically associates with and activates HYAL2, consequently activating the Akt1 and mitogen-activated protein kinase-1 pathways, leading to oncogenic transformation. |
