Recombinant human Cystatin-B protein (His tag N-Terminus)

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

Cystatin-B also known as STEFIN-B is a protease inhibitor with a molecular mass of approximately 11 kilodaltons. It belongs to the family of cystatins which are expressed widely in human tissues with notable presence in the brain liver and kidneys. Cystatin-B acts by inhibiting cysteine proteases preventing them from degrading proteins indiscriminately. The inhibition is important for maintaining cellular protein balance and integrity.

Biological function summary

Cysteine protease inhibition by Cystatin-B protects cells from uncontrolled proteolysis which can lead to tissue damage. This protein plays an important role in the regulation of various cellular processes including apoptosis phagocytosis and the response to oxidative stress. It does not form part of a larger complex but interacts directly with its target proteases to exert its inhibitory effects.

Pathways

Cystatin-B influences proteolytic pathways by modulating the activity of cysteine proteases such as cathepsins. By inhibiting these enzymes Cystatin-B participates in the regulation of the lysosomal degradation pathway and apoptotic pathways which are important for cellular turnover and programmed cell death. Cathepsins particularly cathepsin B and L are related proteins that are significantly modulated through their interaction with Cystatin-B.

Mutations or dysregulation of Cystatin-B are associated with progressive myoclonus epilepsy and certain neurodegenerative diseases. The lack of functional Cystatin-B leads to excessive activity of proteases like cathepsin B resulting in increased proteolysis and neuronal damage. In some cases this can also connect to disorders involving oxidative stress exacerbating the detrimental cycle of cellular injury.