keratin, type I cytoskeletal 19; cytokeratin-19; CK-19; keratin-19; K19 (KRT19)

Function

• role in the organization of myofibers
• together with KRT8, helps to link the contractile apparatus to dystrophin at the costameres of striated muscle
• interacts with PNN & the actin-binding domain of DMD
• interacts with HCV core protein

Structure

• type 1 cytokeratin
• heterotetramer of 2 type 1 & 2 type 2 cytokeratins
• differs from all other intermediate filament proteins in lacking the C-terminal tail domain
• belongs to the intermediate filament family
• lowest molecular weight of keratin group

Expression

• found in simple epithelia, most glandular & basal layer of squamous epithelium of mucosa & epidermis
• expressed in a defined zone of basal keratinocytes in the deep outer root sheath of hair follicles
• also observed in sweat gland & mammary gland ductal & secretory cells, bile ducts, gastrointestinal tract, bladder urothelium, oral epithelia, esophagus, ecto- cervical epithelium (at protein level)
• expressed in epidermal basal cells, in nipple epidermis & a defined region of the hair follicle
• also seen in a subset of vascular wall cells in both the veins & artery of human umbilical cord, & in umbilical cord vascular smooth muscle
• observed in muscle fibers accumulating in the costameres of myoplasm at the sarcolemma in structures that contain dystrophin & spectrin
• present in hair follicles at all stages of development

More general terms

• cytokeratin, epithelial keratins or soft alpha-keratins
• phosphoprotein

Database

• UniProt: http://www.uniprot.org/uniprot/P08727.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=3880
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:3880
• OMIM: https://mirror.omim.org/entry/148020