ID   K1C18_PROAT             Reviewed;         438 AA.
AC   Q5K2N9;
DT   29-MAY-2007, integrated into UniProtKB/Swiss-Prot.
DT   15-FEB-2005, sequence version 1.
DT   25-MAY-2022, entry version 47.
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:0000312|EMBL:CAH05048.1};
OS   Protopterus aethiopicus (Marbled lungfish).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Dipnomorpha; Ceratodontiformes; Lepidosirenoidei; Protopteridae;
OC   Protopterus.
OX   NCBI_TaxID=7886;
RN   [1] {ECO:0000305, ECO:0000312|EMBL:CAH05048.1}
RP   NUCLEOTIDE SEQUENCE [MRNA], TISSUE SPECIFICITY, AND IDENTIFICATION BY MASS
RP   SPECTROMETRY.
RC   TISSUE=Skin {ECO:0000269|PubMed:15819414};
RX   PubMed=15819414; DOI=10.1016/j.ejcb.2004.12.006;
RA   Schaffeld M., Bremer M., Hunzinger C., Markl J.;
RT   "Evolution of tissue-specific keratins as deduced from novel cDNA sequences
RT   of the lungfish Protopterus aethiopicus.";
RL   Eur. J. Cell Biol. 84:363-377(2005).
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 at low levels in skin.
CC       {ECO:0000269|PubMed:15819414}.
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}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   EMBL; AJ785792; CAH05048.1; -; mRNA.
DR   AlphaFoldDB; Q5K2N9; -.
DR   SMR; Q5K2N9; -.
DR   PRIDE; Q5K2N9; -.
DR   GO; GO:0005882; C:intermediate filament; IEA:UniProtKB-KW.
DR   GO; GO:0005198; F:structural molecule activity; IEA:InterPro.
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; PS51842; IF_ROD_2; 1.
PE   1: Evidence at protein level;
KW   Coiled coil; Intermediate filament; Keratin; Phosphoprotein.
FT   INIT_MET        1
FT                   /note="Removed"
FT                   /evidence="ECO:0000250|UniProtKB:P05783"
FT   CHAIN           2..438
FT                   /note="Keratin, type I cytoskeletal 18"
FT                   /evidence="ECO:0000250|UniProtKB:P05783"
FT                   /id="PRO_0000289075"
FT   DOMAIN          84..395
FT                   /note="IF rod"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01188"
FT   REGION          4..83
FT                   /note="Head"
FT                   /evidence="ECO:0000255"
FT   REGION          84..119
FT                   /note="Coil 1A"
FT                   /evidence="ECO:0000255"
FT   REGION          120..136
FT                   /note="Linker 1"
FT                   /evidence="ECO:0000255"
FT   REGION          137..228
FT                   /note="Coil 1B"
FT                   /evidence="ECO:0000255"
FT   REGION          229..252
FT                   /note="Linker 12"
FT                   /evidence="ECO:0000255"
FT   REGION          253..393
FT                   /note="Coil 2"
FT                   /evidence="ECO:0000255"
FT   REGION          394..438
FT                   /note="Tail"
FT                   /evidence="ECO:0000255"
FT   SITE            242..243
FT                   /note="Cleavage; by caspases"
FT                   /evidence="ECO:0000250"
FT   SITE            335
FT                   /note="Stutter"
FT                   /evidence="ECO:0000255"
SQ   SEQUENCE   438 AA;  48990 MW;  2959D3A9FCFFCB40 CRC64;
     MYSAVSSRST VVSSRPLSSS RSLVVSSSYP KMSTASTTYS GVASSGSRIS STRYSTIGSA
     LGGAGGFGTR SSLTLSGNAV ISNEKETMQD LNDRLSNYLE TVRRLENANQ QLEIQIREAM
     EKRGPSVRDY SNYEKIIKEL RDQIYDTTVD NARLVLAIDN ARLAADDFRV KWEAELAIRQ
     SVDSDINGLR KVIDDTNLGR LQLESEIEVL KEELVFIKKN HEDEVIALRN QVNSCGVQVD
     LDAPKGTDLA EIMATLRAEY EAMINKNKDD AEHWYQSKVE TFQVETVQNT EALQTAKTEL
     SDLRRRIQSL EIELESNRSM RASLEDTLRD TELRYAMEME RLGALVSRIE AELAQVRTDM
     QRQAQDYEVL LNAKMKLEAE IATYRHLLGG EDSDTLSLQD ALSAMKVSNV QTVQKIVVTT
     QKLVDGKVVE DSTVTETK