CST4

The cystatin superfamily encompasses proteins that contain multiple cystatin-like sequences. Some of the members are active cysteine protease inhibitors, while others have lost or perhaps never acquired this inhibitory activity. There are three inhibitory families in the superfamily, including the type 1 cystatins (stefins), type 2 cystatins and the kininogens. The type 2 cystatin proteins are a class of cysteine proteinase inhibitors found in a variety of human fluids and secretions. The cystatin locus on chromosome 20 contains the majority of the type 2 cystatin genes and pseudogenes. This gene is located in the cystatin locus and encodes a type 2 salivary cysteine peptidase inhibitor. The protein is an S-type cystatin, based on its high level of expression in saliva, tears and seminal plasma. The specific role in these fluids is unclear but antibacterial and antiviral activity is present, consistent with a protective function. [provided by RefSeq, Jul 2008]

A protein domain is a distinct structural or functional region within a protein that can evolve, function, and exist independently of the rest of the protein chain. These domains in human CST4 often fold into stable, three-dimensional structures and are associated with specific biological functions, such as binding to DNA, other proteins, or small molecules.

The most significant associations for this gene, including commonly observed domains, pathway involvement, and functional highlights based on current data.

Locations within the cell where the protein is known or predicted to be active, providing insight into its function and cellular context.

Describes the biological processes, cellular components, and molecular functions associated with the human CST4 gene, providing context for its role in the cell.