cystatiiniperheet

Cystatin C is a small, cysteine-rich protein that is primarily produced by the liver and kidneys. It plays a crucial role in the regulation of cell growth and differentiation, as well as in the maintenance of extracellular matrix integrity. Cystatin C is a member of the cystatin superfamily, which includes other proteins such as cystatin A, stefin A, and stefin B. These proteins share a common structure and function, which is to inhibit cysteine proteases, a class of enzymes involved in various biological processes.

Cystatin C is a potent inhibitor of cathepsin B, a lysosomal cysteine protease that is involved in the degradation of intracellular proteins. By inhibiting cathepsin B, cystatin C helps to regulate the turnover of intracellular proteins and maintain the integrity of cellular structures. Cystatin C is also involved in the regulation of cell growth and differentiation, as it can inhibit the activity of matrix metalloproteinases, a family of enzymes that degrade the extracellular matrix.

Cystatin C levels in the blood are used as a marker of kidney function. Elevated levels of cystatin C in the blood are indicative of kidney dysfunction, as the kidneys are the primary site of cystatin C production. Cystatin C is a more sensitive marker of kidney function than creatinine, as it is less affected by muscle mass and age. However, cystatin C levels can also be elevated in other conditions, such as inflammation and certain types of cancer.

Cystatin C is also involved in the regulation of immune function. It has been shown to inhibit the activity of natural killer cells, a type of immune cell that plays a crucial role in the defense against viral infections and cancer. Cystatin C may also play a role in the regulation of inflammation, as it can inhibit the activity of certain inflammatory mediators.

In summary, cystatin C is a small, cysteine-rich protein that plays a crucial role in the regulation of cell growth and differentiation, the maintenance of extracellular matrix integrity, and the regulation of immune function. Cystatin C levels in the blood are used as a marker of kidney function, and elevated levels are indicative of kidney dysfunction. Cystatin C is a member of the cystatin superfamily, which includes other proteins that share a common structure and function.