Keratin 8

Keratin 8, type II
Identifiers
Symbols	KRT8 ; CARD2; CK-8; CK8; CYK8; K2C8; K8; KO
External IDs	OMIM: 148060 MGI: 96705 HomoloGene: 55643 GeneCards: KRT8 Gene
Gene ontology Molecular function • structural molecule activity • protein binding • protein complex binding • scaffold protein binding Cellular component • nucleus • nucleoplasm • cytoplasm • intermediate filament • cell-cell junction • dystrophin-associated glycoprotein complex • nuclear matrix • Z disc • sarcolemma • costamere • keratin filament • intermediate filament cytoskeleton • extracellular exosome Biological process • viral process • tumor necrosis factor-mediated signaling pathway • sarcomere organization • response to hydrostatic pressure • response to other organism • cell differentiation involved in embryonic placenta development • extrinsic apoptotic signaling pathway • hepatocyte apoptotic process Sources: Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	3856	16691
Ensembl	ENSG00000170421	ENSMUSG00000049382
UniProt	P05787	P11679
RefSeq (mRNA)	NM_001256282	NM_031170
RefSeq (protein)	NP_001243211	NP_112447
Location (UCSC)	Chr 12: 52.9 – 52.95 Mb	Chr 15: 102 – 102 Mb
PubMed search	[1]	[2]

Keratin, type II cytoskeletal 8 also known as cytokeratin-8 (CK-8) or keratin-8 (K8) is a keratin protein that is encoded in humans by the KRT8 gene. It is often paired with keratin 18.

Utility as an immunohistochemical stain

Antibodies to CK8 (e.g. CAM 5.2) can be used to differentiate lobular carcinoma of the breast from ductal carcinoma of the breast. CAM 5.2, an antibody that reacts with an epitope found on both CK8 and CK18, is used in immunohistochemistry to demonstrate certain forms of cancer. In normal tissue, it reacts mainly with secretory epithelia, but not with squamous epithelium, such as that found in the skin, cervix, and esophagus. However, it also reacts with a range of malignant cells, including those derived from secretory epithelia, but also some squamous carcinomata, such as spindle cell carcinoma. It is considered useful in identifying microscopic metastases of breast carcinoma in lymph nodes, and in distinguishing Paget's disease from malignant melanoma. It also reacts with neuroendocrine tumors.

Keratin 8 is often used together with keratin 18 and keratin 19 to differentiate cells of epithelial origin from hematopoietic cells in tests that enumerate circulating tumor cells in blood.

Interactions

Keratin 8 has been shown to interact with MAPK14, Pinin and PPL.

See also

• Immunohistochemistry

External links

• Keratin-8 at the US National Library of Medicine Medical Subject Headings (MeSH)