ID   K1C18_SCYST             Reviewed;         415 AA.
AC   O57611;
DT   29-MAY-2007, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-1998, sequence version 1.
DT   25-MAY-2022, entry version 63.
DE   RecName: Full=Keratin, type I cytoskeletal 18;
DE   AltName: Full=Cytokeratin-18;
DE            Short=CK-18;
DE   AltName: Full=Keratin-18;
DE            Short=K18;
GN   Name=krt18 {ECO:0000250|UniProtKB:P05783};
OS   Scyliorhinus stellaris (Nursehound) (Greater spotted dogfish).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Chondrichthyes;
OC   Elasmobranchii; Galeomorphii; Galeoidea; Carcharhiniformes; Scyliorhinidae;
OC   Scyliorhinus.
OX   NCBI_TaxID=68454;
RN   [1] {ECO:0000305, ECO:0000312|EMBL:CAA74980.1}
RP   NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 85-94; 112-124; 126-145;
RP   155-162; 281-288 AND 332-340, AND TISSUE SPECIFICITY.
RX   PubMed=9840456; DOI=10.1016/s0171-9335(98)80074-5;
RA   Schaffeld M., Lobbecke A., Lieb B., Markl J.;
RT   "Tracing keratin evolution: catalog, expression patterns and primary
RT   structure of shark (Scyliorhinus stellaris) keratins.";
RL   Eur. J. Cell Biol. 77:69-80(1998).
RN   [2] {ECO:0000305}
RP   TISSUE SPECIFICITY.
RX   PubMed=15503859; DOI=10.1078/0171-9335-00395;
RA   Schaffeld M., Hoffling S., Jurgen M.;
RT   "Sequence, evolution and tissue expression patterns of an epidermal type I
RT   keratin from the shark Scyliorhinus stellaris.";
RL   Eur. J. Cell Biol. 83:359-368(2004).
CC   -!- FUNCTION: When phosphorylated, plays a role in filament reorganization.
CC       {ECO:0000250}.
CC   -!- SUBUNIT: Heterotetramer of two type I and two type II keratins.
CC       Keratin-18 associates with keratin-8 (By similarity). {ECO:0000250}.
CC   -!- TISSUE SPECIFICITY: Expressed in stratified and complex epithelia such
CC       as epidermis, mouth and pharyngeal mucosa, mucosa of anterior
CC       esophagus, rectal mucosa and gland canals, gill mucosae, gill squamous
CC       epithelium and secondary lamellae, uterus mucosa, cornea, conjunctiva,
CC       outermost layer of Sclera and in olfactory epithelium. Also expressed
CC       in simple epithelia and epitheloid cells such as lateral line canal
CC       (mantle cells, neuromast), dura mater (meninges) and ampullae of
CC       Lorenzini. {ECO:0000269|PubMed:15503859, ECO:0000269|PubMed:9840456}.
CC   -!- PTM: Phosphorylated. {ECO:0000250}.
CC   -!- PTM: Proteolytically cleaved by caspases during epithelial cell
CC       apoptosis. {ECO:0000250}.
CC   -!- MISCELLANEOUS: There are two types of cytoskeletal and microfibrillar
CC       keratin: I (acidic; 40-55 kDa) and II (neutral to basic; 56-70 kDa).
CC       {ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the intermediate filament family.
CC       {ECO:0000255|PROSITE-ProRule:PRU01188}.
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DR   EMBL; Y14647; CAA74980.1; -; mRNA.
DR   AlphaFoldDB; O57611; -.
DR   SMR; O57611; -.
DR   PRIDE; O57611; -.
DR   GO; GO:0005882; C:intermediate filament; IEA:UniProtKB-KW.
DR   GO; GO:0005198; F:structural molecule activity; IEA:InterPro.
DR   InterPro; IPR018039; IF_conserved.
DR   InterPro; IPR039008; IF_rod_dom.
DR   InterPro; IPR027695; Keratin-18.
DR   InterPro; IPR002957; Keratin_I.
DR   PANTHER; PTHR23239; PTHR23239; 1.
DR   PANTHER; PTHR23239:SF349; PTHR23239:SF349; 1.
DR   Pfam; PF00038; Filament; 1.
DR   PRINTS; PR01248; TYPE1KERATIN.
DR   SMART; SM01391; Filament; 1.
DR   PROSITE; PS00226; IF_ROD_1; 1.
DR   PROSITE; PS51842; IF_ROD_2; 1.
PE   1: Evidence at protein level;
KW   Coiled coil; Direct protein sequencing; Intermediate filament; Keratin;
KW   Phosphoprotein.
FT   INIT_MET        1
FT                   /note="Removed"
FT                   /evidence="ECO:0000250|UniProtKB:P05783"
FT   CHAIN           2..415
FT                   /note="Keratin, type I cytoskeletal 18"
FT                   /evidence="ECO:0000250|UniProtKB:P05783"
FT                   /id="PRO_0000289076"
FT   DOMAIN          67..378
FT                   /note="IF rod"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01188"
FT   REGION          1..25
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          2..66
FT                   /note="Head"
FT                   /evidence="ECO:0000255"
FT   REGION          67..102
FT                   /note="Coil 1A"
FT                   /evidence="ECO:0000255"
FT   REGION          103..119
FT                   /note="Linker 1"
FT                   /evidence="ECO:0000255"
FT   REGION          120..211
FT                   /note="Coil 1B"
FT                   /evidence="ECO:0000255"
FT   REGION          212..235
FT                   /note="Linker 12"
FT                   /evidence="ECO:0000255"
FT   REGION          236..373
FT                   /note="Coil 2"
FT                   /evidence="ECO:0000255"
FT   REGION          374..415
FT                   /note="Tail"
FT                   /evidence="ECO:0000255"
FT   SITE            225..226
FT                   /note="Cleavage; by caspases"
FT                   /evidence="ECO:0000250"
FT   SITE            318
FT                   /note="Stutter"
FT                   /evidence="ECO:0000255"
SQ   SEQUENCE   415 AA;  46792 MW;  D02F98DF51095D30 CRC64;
     MTYRGYTSLS SHSGPMSIRR SMPLQSSASS ISGYGQRMAV SRISRVASLG SSSSSAAGIG
     MGGVGNQKET MQDLNDRLAT YLEKVHSLET GNAKLELQIK EHLDARGPSF RDWSIYEKPL
     NELRKEVYDM TVDNARLILQ IDNARLAADD FRVKWESELS IRQSVENDIN GLRKVIDDTN
     IGRLHLETEI ESLKEELIYI RKNHDEEVKA LRSQVADSSV HVEVDSAPGP DLSKVLAEIR
     KEYEGVAQKN KDDAEIWYKN QMDGYKVEVK HNTDELCSAK VQVTELHRQI QSLEVELESL
     LSMKNSLEGT LRDTELRYEM ELQTINGMIA KLEADLHQIR GDMQAQVREY EILLNIKMKL
     EAEIATYRRL LDGEDINTLV ESTSGVTSQT IKKTIVTTQK VVDGKIVSDE TVQIN