S1 proteinisa family of low molecular weight protein found in vertebrates characterized bytwoEF-hand calcium-binding motifs. There are at least 21 different S1proteins, and the name is derived from the fact that the protein is1%solublein ammonium sulfateat neutralpH. Most S1 proteins aredisulfide-linked homodimer, and is normally present in cells derived fromtheneural crest, chondrocytes, macrophages, dendritic cells, etc. S1proteins have been implicated in a variety of intracellular and extracellularfunctions. They are involved in regulation of protein phosphorylation,transcription factors, the dynamics of cytoskeleton constituents, enzymeactivities, cell growth and differentiation, and the inflammatory response. Human ProteinS1-A8, also known as S1 calcium-binding protein A8, Cystic fibrosisantigen, Migration inhibitory factor-related protein 8, S1A8, and CAGA, is amember of the S-1 family. S1A8 plays a role in various functions of myeloidcells by forming a heterocomplex with S1A9. S1A8 and S1A9 are known to beoverexpressed in certain species of carcinomas. S1A8 plays an important rolein dedifferentiation of thyroid carcinoma possibly by forming a complex withS1A9. S1A8 and S1A9 may also play a key role in inflammation-associatedcancer.

aspartylglucosaminidase