ID   K118A_XENLA             Reviewed;         428 AA.
AC   P08802; Q6INH6; Q8AVI2;
DT   01-NOV-1988, integrated into UniProtKB/Swiss-Prot.
DT   29-MAY-2007, sequence version 2.
DT   03-AUG-2022, entry version 97.
DE   RecName: Full=Keratin, type I cytoskeletal 18-A;
DE   AltName: Full=Cytokeratin-18-A;
DE            Short=CK-18-A;
DE   AltName: Full=Keratin, type I cytoskeletal endo B;
DE   AltName: Full=Keratin-18-A;
DE            Short=K18-A;
GN   Name=krt18-a;
OS   Xenopus laevis (African clawed frog).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Amphibia;
OC   Batrachia; Anura; Pipoidea; Pipidae; Xenopodinae; Xenopus; Xenopus.
OX   NCBI_TaxID=8355;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RC   TISSUE=Embryo;
RG   NIH - Xenopus Gene Collection (XGC) project;
RL   Submitted (JUN-2004) to the EMBL/GenBank/DDBJ databases.
RN   [2]
RP   NUCLEOTIDE SEQUENCE [MRNA] OF 61-428, TISSUE SPECIFICITY, AND DEVELOPMENTAL
RP   STAGE.
RC   TISSUE=Neurula;
RX   PubMed=2463213; DOI=10.1101/gad.2.7.853;
RA   Laflamme S.E., Jamrich M., Richter K., Sargent T.D., Dawid I.B.;
RT   "Xenopus endo B is a keratin preferentially expressed in the embryonic
RT   notochord.";
RL   Genes Dev. 2:853-862(1988).
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.
CC   -!- TISSUE SPECIFICITY: Expressed at high levels in notochord and low
CC       levels in adult liver. {ECO:0000269|PubMed:2463213}.
CC   -!- DEVELOPMENTAL STAGE: Expression is concentrated in the notochord with
CC       strongest expression in the embryo at stages 17 to 27, and slightly
CC       less in the endoderm. It is present in the oocyte and expression
CC       increases from late gastrula. Accumulation peaks by late neurula and is
CC       greatly reduced by the tadpole stage. {ECO:0000269|PubMed:2463213}.
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   -!- SIMILARITY: Belongs to the intermediate filament family.
CC       {ECO:0000255|PROSITE-ProRule:PRU01188}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=AAH42269.1; Type=Erroneous initiation; Evidence={ECO:0000305};
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DR   EMBL; BC042269; AAH42269.1; ALT_INIT; mRNA.
DR   EMBL; BC072305; AAH72305.1; -; mRNA.
DR   EMBL; Y00230; CAA68372.1; -; mRNA.
DR   PIR; A28825; A28825.
DR   RefSeq; NP_001082454.1; NM_001088985.1.
DR   AlphaFoldDB; P08802; -.
DR   SMR; P08802; -.
DR   BioGRID; 99814; 1.
DR   PRIDE; P08802; -.
DR   GeneID; 398482; -.
DR   KEGG; xla:398482; -.
DR   CTD; 398482; -.
DR   Xenbase; XB-GENE-6256308; krt18.1.S.
DR   OrthoDB; 711591at2759; -.
DR   Proteomes; UP000186698; Chromosome 2S.
DR   Bgee; 398482; Expressed in neurula embryo and 19 other tissues.
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   2: Evidence at transcript level;
KW   Coiled coil; Intermediate filament; Keratin; Phosphoprotein;
KW   Reference proteome.
FT   INIT_MET        1
FT                   /note="Removed"
FT                   /evidence="ECO:0000250"
FT   CHAIN           2..428
FT                   /note="Keratin, type I cytoskeletal 18-A"
FT                   /id="PRO_0000063669"
FT   DOMAIN          79..389
FT                   /note="IF rod"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01188"
FT   REGION          2..78
FT                   /note="Head"
FT                   /evidence="ECO:0000250"
FT   REGION          24..45
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          79..114
FT                   /note="Coil 1A"
FT   REGION          115..130
FT                   /note="Linker 1"
FT   REGION          131..222
FT                   /note="Coil 1B"
FT   REGION          223..246
FT                   /note="Linker 12"
FT   REGION          247..384
FT                   /note="Coil 2"
FT   REGION          385..428
FT                   /note="Tail"
FT   SITE            236..237
FT                   /note="Cleavage; by caspases"
FT                   /evidence="ECO:0000250"
FT   SITE            329
FT                   /note="Stutter"
FT   CONFLICT        228
FT                   /note="S -> T (in Ref. 2; CAA68372)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        275..276
FT                   /note="EH -> DD (in Ref. 2; CAA68372)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   428 AA;  47470 MW;  90953178F1E6C560 CRC64;
     MSSSRSVYSS SSVVGGSPYR SLSSAPRFTP GSSAASVHAG AGGSGARISV SRVSTVGSGF
     GGGFSGASNV NLFGGVQNEK ETMQDLNDRL ASYLERVRSL ESANKKLEVQ IRQHTEKKGP
     AKDWSPYYMT IEDLKKQVFN SIVENSQLVL QIDNARLAAD DFRVKYESEV AIRMSVETDI
     GGLRKLIDDT NISRLNLENE FESLKEELIF LKKNHQDDVN ELQAQIASSA VTVEVDAPKS
     QDLGKIMADL RAQYDEMAQK NREDVEKLYQ SKVEEHTVQV NLDAEALHTA KSSVTELRRT
     MQSLEIELES LRNQKASLEG TLHDTEARYA MELEMLGGTA MALETELVQV RNDCQRQQQE
     YQALLNTKMK LEAEIQTYRR LLEGDSFDLQ DAVPVVTTQT VKKVITTTQR LVDGKVVAES
     NNTEVIKS