1CYU, 1CYV, 1DVC, 1DVD, 1GD3, 1GD4, 1N9J, 1NB3, 1NB5, 3K9M, 3KFQ, 3KSE147576770ENSG00000121552ENSMUSG00000095620P01040Q9D8D6NM_005213NM_029733NM_001384090NP_005204NP_084009NP_001371019Cystatin-A is a protein that in humans is encoded by the CSTA gene.

[5][6] The cystatin superfamily encompasses proteins that contain multiple cystatin-like sequences.

This gene encodes a stefin that functions as a cysteine protease inhibitor, forming tight complexes with papain and the cathepsins B, H, and L. The protein is one of the precursor proteins of cornified cell envelope in keratinocytes and plays a role in epidermal development and maintenance.

Stefins have been proposed as prognostic and diagnostic tools for cancer.

[8][9] This article on a gene on human chromosome 3 is a stub.