CST4

Identifiers

Aliases
CST4

External IDs
GeneCards: CST4

Gene ontology

Molecular function
• peptidase inhibitor activity
• cysteine-type endopeptidase inhibitor activity

Cellular component
• extracellular region
• extracellular exosome
• extracellular space

Biological process
• negative regulation of proteolysis
• retina homeostasis
• negative regulation of peptidase activity
• detection of chemical stimulus involved in sensory perception of bitter taste
• negative regulation of endopeptidase activity

Sources:Amigo / QuickGO

Orthologs

Species
Human
Mouse

Entrez

1472

n/a

Ensembl

ENSG00000101441

n/a

UniProt

P01036

n/a

RefSeq (mRNA)

NM_001899

n/a

RefSeq (protein)

NP_001890

n/a

Location (UCSC)
Chr 20: 23.69 – 23.69 Mb
n/a

PubMed search
[1]
n/a

Wikidata

View/Edit Human

Cystatin-S is a protein that in humans is encoded by the CST4 gene.[2][3]
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.[3]
References[edit]

^ “Human PubMed Reference:”. 
^ Saitoh E, Isemura S, Sanada K, Ohnishi K (Apr 1992). “The human cystatin gene family: cloning of three members and evolutionary relationship between cystatins and Bowman-Birk type proteinase inhibitors”. Biomed Biochim Acta. 50 (4–6): 599–605. PMID 1801729. 
^ a b “Entrez Gene: CST4 cystatin S”. 

External links[edit]

The MEROPS online database for peptidases and their inhibitors: I25.008

Further reading[edit]

Brown WM, Dziegielewska