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Protein

Keratin, type I cytoskeletal 18

Gene

Krt18

Organism
Rattus norvegicus (Rat)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

When phosphorylated, plays a role in filament reorganization. Involved in the delivery of mutated CFTR to the plasma membrane. Together with KRT8, is involved in interleukin-6 (IL-6)-mediated barrier protection (By similarity). Involved in the uptake of thrombin-antithrombin complexes by hepatic cells.By similarity1 Publication

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sitei264StutterSequence analysis1
Sitei324StutterSequence analysis1

GO - Molecular functioni

GO - Biological processi

Complete GO annotation...

Enzyme and pathway databases

ReactomeiR-RNO-6805567. Keratinization.
R-RNO-6809371. Formation of the cornified envelope.

Names & Taxonomyi

Protein namesi
Recommended name:
Keratin, type I cytoskeletal 18
Alternative name(s):
Cytokeratin-18
Short name:
CK-18
Keratin-18
Short name:
K18
Gene namesi
Name:Krt18By similarity
Synonyms:Krt1-18Imported
OrganismiRattus norvegicus (Rat)
Taxonomic identifieri10116 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresGliresRodentiaSciurognathiMuroideaMuridaeMurinaeRattus
Proteomesi
  • UP000002494 Componenti: Chromosome 7

Organism-specific databases

RGDi619935. Krt18.

Subcellular locationi

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Cytoplasm, Intermediate filament, Keratin, Nucleus

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Initiator methionineiRemovedBy similarity
ChainiPRO_00000636682 – 423Keratin, type I cytoskeletal 18Add BLAST422

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei2N-acetylserineBy similarity1
Modified residuei7PhosphoserineBy similarity1
Modified residuei11PhosphoserineBy similarity1
Modified residuei16PhosphoserineBy similarity1
Modified residuei19PhosphoserineCombined sources1
Modified residuei31Phosphoserine; alternateCombined sources1
Glycosylationi31O-linked (GlcNAc); alternateBy similarity1
Modified residuei32Phosphoserine; alternateBy similarity1
Glycosylationi32O-linked (GlcNAc); alternateBy similarity1
Modified residuei35PhosphoserineCombined sources1
Modified residuei37PhosphotyrosineBy similarity1
Modified residuei43PhosphoserineBy similarity1
Modified residuei46Omega-N-methylarginineBy similarity1
Modified residuei50Phosphoserine; alternateBy similarity1
Glycosylationi50O-linked (GlcNAc); alternateBy similarity1
Modified residuei52Phosphoserine; by MAPKAPK2 and MAPKAPK3By similarity1
Modified residuei57PhosphoserineCombined sources1
Modified residuei60PhosphoserineBy similarity1
Modified residuei85PhosphoserineBy similarity1
Modified residuei124N6-acetyllysineBy similarity1
Modified residuei137PhosphoserineBy similarity1
Modified residuei170PhosphoserineBy similarity1
Modified residuei295PhosphothreonineBy similarity1
Modified residuei384PhosphoserineBy similarity1
Modified residuei391PhosphoserineBy similarity1
Modified residuei392PhosphoserineBy similarity1
Modified residuei394PhosphoserineBy similarity1
Modified residuei397PhosphothreonineBy similarity1

Post-translational modificationi

Phosphorylation increases by IL-6.By similarity
Proteolytically cleaved by caspases during epithelial cell apoptosis. Cleavage occurs at Asp-231 by either caspase-3, caspase-6 or caspase-7 (By similarity).By similarity
Dephosphorylated by ethanol.1 Publication
O-GlcNAcylation increases solubility, and decreases stability by inducing proteasomal degradation.By similarity

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sitei231 – 232Cleavage; by caspase-3, caspase-6 or caspase-7By similarity2

Keywords - PTMi

Acetylation, Glycoprotein, Methylation, Phosphoprotein

Proteomic databases

PaxDbiQ5BJY9.
PRIDEiQ5BJY9.

PTM databases

iPTMnetiQ5BJY9.
PhosphoSitePlusiQ5BJY9.

Expressioni

Tissue specificityi

Expressed on the plasma membrane of hepatocytes and in the narrow apical portions of supporting cells in the vomeronasal sensory epithelium. Detected in the type III alveolar cells of the lung, in the proliferative crypt epithelium of the small intestine and in the older intragemmal cells of the tongue.7 Publications

Developmental stagei

Expression first detected in the male gonad at 13.5 dpc, at the onset of testicular differentiation, and at 17 dpc in cell aggregates of the early ovary; then only in some cord cells of the older ovary. Expressed in fetal lung epithelium at 20 dpc. Detected at 13 dpc, sparsely distributed throughout the cytoplasm in the single layer of periderm cells covering the dorsal epithelium of the fetal tongue. Expression increases in the lingual periderm cells at 17 dpc and then disappears at 19 dpc coinciding with the disappearance of the periderm cells at the onset of squamous stratification of the lingual epithelium. Expressed at day 2-3 postnatally in older, elongated taste bud cells and at day 5, uniformly distributed throughout the epithelium of villi, intervillus epithelium and developing crypt buds of the small intestine.7 Publications

Inductioni

By IL-6 (By similarity). By fibronectin.By similarity1 Publication

Gene expression databases

BgeeiENSRNOG00000047393.
GenevisibleiQ5BJY9. RN.

Interactioni

Subunit structurei

Heterotetramer of two type I and two type II keratins. KRT18 associates with KRT8. Interacts with PNN, HCV core protein and mutated CFTR. Interacts with YWHAE, YWHAH and YWHAZ only when phosphorylated. Interacts with DNAJB6, TCHP and TRADD (By similarity). Interacts with the thrombin-antithrombin complex. Interacts with FAM83H (By similarity). Interacts with EPPK1 (By similarity).By similarity1 Publication

Protein-protein interaction databases

STRINGi10116.ENSRNOP00000067234.

Structurei

3D structure databases

ProteinModelPortaliQ5BJY9.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni2 – 71HeadSequence analysisAdd BLAST70
Regioni62 – 366Necessary for interaction with PNNBy similarityAdd BLAST305
Regioni69 – 121Interaction with TRADDBy similarityAdd BLAST53
Regioni72 – 380RodSequence analysisAdd BLAST309
Regioni72 – 107Coil 1ASequence analysisAdd BLAST36
Regioni108 – 125Linker 1Sequence analysisAdd BLAST18
Regioni126 – 217Coil 1BSequence analysisAdd BLAST92
Regioni218 – 241Linker 12Sequence analysisAdd BLAST24
Regioni236 – 384Interaction with DNAJB6By similarityAdd BLAST149
Regioni242 – 380Coil 2Sequence analysisAdd BLAST139
Regioni381 – 423TailSequence analysisAdd BLAST43

Sequence similaritiesi

Belongs to the intermediate filament family.Sequence analysis

Keywords - Domaini

Coiled coil

Phylogenomic databases

eggNOGiENOG410IEYR. Eukaryota.
ENOG4111DJ8. LUCA.
GeneTreeiENSGT00760000119046.
HOGENOMiHOG000230975.
HOVERGENiHBG013015.
InParanoidiQ5BJY9.
KOiK07604.
OMAiRAKYEKM.
OrthoDBiEOG091G0A3U.
PhylomeDBiQ5BJY9.

Family and domain databases

InterProiIPR001664. IF.
IPR018039. Intermediate_filament_CS.
IPR027695. Keratin-18.
IPR002957. Keratin_I.
[Graphical view]
PANTHERiPTHR23239. PTHR23239. 1 hit.
PTHR23239:SF35. PTHR23239:SF35. 1 hit.
PfamiPF00038. Filament. 1 hit.
[Graphical view]
PRINTSiPR01248. TYPE1KERATIN.
SMARTiSM01391. Filament. 1 hit.
[Graphical view]
PROSITEiPS00226. IF. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

Q5BJY9-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MSFTTRSTTF STNYRSLGSV RTPSQRVRPA SSAASVYAGA GGSGSRISVS
60 70 80 90 100
RSVWGGSVGS AGLAGMGGVQ TEKETMQDLN DRLASYLDKV KNLETENRRL
110 120 130 140 150
ESKIREYLEK RGPQGVRDWG HYFKTIEDLR AQIFANSVDN ARIVLQIDNA
160 170 180 190 200
RLAADDFRVK YETELAMRQS VESDIHGLRK VVDDTNITRL QLETEIEALK
210 220 230 240 250
EELLFMKKNH EEEVQGLEAQ IASSGLTVEV DAPKSQDLSK IMADIRAQYE
260 270 280 290 300
QLAQKNREEL DKYWSQQIEE STTVVTTKSA EIRDAETTLL ELRRTLQTLE
310 320 330 340 350
IDLDSMKNQN INLENNLGEV EARYRVQMEQ LNGVLLHLES ELAQTRAEGQ
360 370 380 390 400
RQTQEYEALL NIKVKLEAEI ATYRRLLEDG DDFSLNDALD SSNSMQTVQR
410 420
TTTRKVVDGK VVSETNDTRV LRH
Length:423
Mass (Da):47,761
Last modified:January 23, 2007 - v3
Checksum:i793F0BAA275CCA4E
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti125T → I in CAA57204 (PubMed:8541209).Curated1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
BC091275 mRNA. Translation: AAH91275.1.
X81448 mRNA. Translation: CAA57204.1.
RefSeqiNP_446428.1. NM_053976.1.
UniGeneiRn.103924.

Genome annotation databases

EnsembliENSRNOT00000073951; ENSRNOP00000067234; ENSRNOG00000047393.
GeneIDi294853.
KEGGirno:294853.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
BC091275 mRNA. Translation: AAH91275.1.
X81448 mRNA. Translation: CAA57204.1.
RefSeqiNP_446428.1. NM_053976.1.
UniGeneiRn.103924.

3D structure databases

ProteinModelPortaliQ5BJY9.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

STRINGi10116.ENSRNOP00000067234.

PTM databases

iPTMnetiQ5BJY9.
PhosphoSitePlusiQ5BJY9.

Proteomic databases

PaxDbiQ5BJY9.
PRIDEiQ5BJY9.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENSRNOT00000073951; ENSRNOP00000067234; ENSRNOG00000047393.
GeneIDi294853.
KEGGirno:294853.

Organism-specific databases

CTDi3875.
RGDi619935. Krt18.

Phylogenomic databases

eggNOGiENOG410IEYR. Eukaryota.
ENOG4111DJ8. LUCA.
GeneTreeiENSGT00760000119046.
HOGENOMiHOG000230975.
HOVERGENiHBG013015.
InParanoidiQ5BJY9.
KOiK07604.
OMAiRAKYEKM.
OrthoDBiEOG091G0A3U.
PhylomeDBiQ5BJY9.

Enzyme and pathway databases

ReactomeiR-RNO-6805567. Keratinization.
R-RNO-6809371. Formation of the cornified envelope.

Miscellaneous databases

PROiQ5BJY9.

Gene expression databases

BgeeiENSRNOG00000047393.
GenevisibleiQ5BJY9. RN.

Family and domain databases

InterProiIPR001664. IF.
IPR018039. Intermediate_filament_CS.
IPR027695. Keratin-18.
IPR002957. Keratin_I.
[Graphical view]
PANTHERiPTHR23239. PTHR23239. 1 hit.
PTHR23239:SF35. PTHR23239:SF35. 1 hit.
PfamiPF00038. Filament. 1 hit.
[Graphical view]
PRINTSiPR01248. TYPE1KERATIN.
SMARTiSM01391. Filament. 1 hit.
[Graphical view]
PROSITEiPS00226. IF. 1 hit.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiK1C18_RAT
AccessioniPrimary (citable) accession number: Q5BJY9
Secondary accession number(s): Q63278
Entry historyi
Integrated into UniProtKB/Swiss-Prot: August 16, 2005
Last sequence update: January 23, 2007
Last modified: November 30, 2016
This is version 103 of the entry and version 3 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program

Miscellaneousi

Miscellaneous

There are two types of cytoskeletal and microfibrillar keratin: I (acidic; 40-55 kDa) and II (neutral to basic; 56-70 kDa).

Keywords - Technical termi

Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.