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Protein

Keratin, type I cytoskeletal 9

Gene

KRT9

Organism
Homo sapiens (Human)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

May serve an important special function either in the mature palmar and plantar skin tissue or in the morphogenetic program of the formation of these tissues. Plays a role in keratin filament assembly.2 Publications

GO - Molecular functioni

  • structural constituent of cytoskeleton Source: ProtInc

GO - Biological processi

  • epidermis development Source: ProtInc
  • intermediate filament organization Source: UniProtKB
  • skin development Source: UniProtKB
  • spermatogenesis Source: Ensembl
Complete GO annotation...

Enzyme and pathway databases

BioCyciZFISH:ENSG00000171403-MONOMER.
ReactomeiR-HSA-6805567. Keratinization.
R-HSA-6809371. Formation of the cornified envelope.

Names & Taxonomyi

Protein namesi
Recommended name:
Keratin, type I cytoskeletal 9
Alternative name(s):
Cytokeratin-9
Short name:
CK-9
Keratin-9
Short name:
K9
Gene namesi
Name:KRT9
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
Proteomesi
  • UP000005640 Componenti: Chromosome 17

Organism-specific databases

HGNCiHGNC:6447. KRT9.

Subcellular locationi

GO - Cellular componenti

  • extracellular exosome Source: UniProtKB
  • extracellular space Source: UniProtKB
  • intermediate filament Source: UniProtKB-KW
  • membrane Source: UniProtKB
  • nucleus Source: UniProtKB
Complete GO annotation...

Keywords - Cellular componenti

Intermediate filament, Keratin

Pathology & Biotechi

Involvement in diseasei

Keratoderma, palmoplantar, epidermolytic (EPPK)23 Publications
The disease is caused by mutations affecting the gene represented in this entry.
Disease descriptionA dermatological disorder characterized by diffuse thickening of the epidermis on the entire surface of palms and soles sharply bordered with erythematous margins. Some patients may present knuckle pads, thick pads of skin appearing over the proximal phalangeal joints.
See also OMIM:144200
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Natural variantiVAR_071977157M → K in EPPK. 1 PublicationCorresponds to variant rs59510579dbSNPEnsembl.1
Natural variantiVAR_036805157M → R in EPPK. 1 PublicationCorresponds to variant rs59510579dbSNPEnsembl.1
Natural variantiVAR_010499157M → T in EPPK. 2 PublicationsCorresponds to variant rs59510579dbSNPEnsembl.1
Natural variantiVAR_010500157M → V in EPPK. 3 PublicationsCorresponds to variant rs58597584dbSNPEnsembl.1
Natural variantiVAR_035438160L → F in EPPK; with knuckle pads. 1 PublicationCorresponds to variant rs28940896dbSNPEnsembl.1
Natural variantiVAR_010501160L → V in EPPK. 1 PublicationCorresponds to variant rs28940896dbSNPEnsembl.1
Natural variantiVAR_036806161N → H in EPPK. 2 PublicationsCorresponds to variant rs59296273dbSNPEnsembl.1
Natural variantiVAR_036807161N → I in EPPK. 2 PublicationsCorresponds to variant rs56707768dbSNPEnsembl.1
Natural variantiVAR_003822161N → K in EPPK. 1 PublicationCorresponds to variant rs57536312dbSNPEnsembl.1
Natural variantiVAR_010502161N → S in EPPK. 2 PublicationsCorresponds to variant rs56707768dbSNPEnsembl.1
Natural variantiVAR_010503161N → Y in EPPK. 1 PublicationCorresponds to variant rs59296273dbSNPEnsembl.1
Natural variantiVAR_036808163R → P in EPPK. 1 PublicationCorresponds to variant rs57758262dbSNPEnsembl.1
Natural variantiVAR_003823163R → Q in EPPK. 6 PublicationsCorresponds to variant rs57758262dbSNPEnsembl.1
Natural variantiVAR_003824163R → W in EPPK. 5 PublicationsCorresponds to variant rs59616921dbSNPEnsembl.1
Natural variantiVAR_036809167Y → WL in EPPK. 1
Natural variantiVAR_003825168L → S in EPPK. 1 PublicationCorresponds to variant rs61157095dbSNPEnsembl.1
Natural variantiVAR_035439171V → M in EPPK. 1 PublicationCorresponds to variant rs57019720dbSNPEnsembl.1
Natural variantiVAR_010504172Q → P in EPPK. 1 PublicationCorresponds to variant rs59878153dbSNPEnsembl.1
Natural variantiVAR_071978406C → R in EPPK. 1 PublicationCorresponds to variant rs77688767dbSNPEnsembl.1
Natural variantiVAR_071979454Y → H in EPPK. 1 PublicationCorresponds to variant rs267607420dbSNPEnsembl.1
Natural variantiVAR_036810458L → F in EPPK. 1 PublicationCorresponds to variant rs58120120dbSNPEnsembl.1
Natural variantiVAR_071980458L → P in EPPK. 1 Publication1

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi163R → QHA: Leads to aggregate formation. 1 Publication1

Keywords - Diseasei

Disease mutation, Palmoplantar keratoderma

Organism-specific databases

DisGeNETi3857.
MalaCardsiKRT9.
MIMi144200. phenotype.
149100. phenotype.
OpenTargetsiENSG00000171403.
Orphaneti2199. Epidermolytic palmoplantar keratoderma.
PharmGKBiPA30235.

Polymorphism and mutation databases

BioMutaiKRT9.
DMDMi239938886.

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00000636401 – 623Keratin, type I cytoskeletal 9Add BLAST623

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei14PhosphoserineBy similarity1
Modified residuei57PhosphoserineBy similarity1

Keywords - PTMi

Phosphoprotein

Proteomic databases

EPDiP35527.
PaxDbiP35527.
PeptideAtlasiP35527.
PRIDEiP35527.
TopDownProteomicsiP35527.

2D gel databases

DOSAC-COBS-2DPAGEP35527.

PTM databases

iPTMnetiP35527.
PhosphoSitePlusiP35527.
SwissPalmiP35527.

Expressioni

Tissue specificityi

Expressed in the terminally differentiated epidermis of palms and soles.1 Publication

Inductioni

Induced by intrinsic regulatory mechanisms and by extrinsic signals from a subset of dermal palmoplantar fibroblasts.1 Publication

Gene expression databases

BgeeiENSG00000171403.
CleanExiHS_KRT9.
ExpressionAtlasiP35527. baseline and differential.
GenevisibleiP35527. HS.

Organism-specific databases

HPAiHPA007261.
HPA009673.

Interactioni

Subunit structurei

Heterotetramer of two type I and two type II keratins.

Protein-protein interaction databases

BioGridi110055. 45 interactors.
IntActiP35527. 19 interactors.
MINTiMINT-4998976.
STRINGi9606.ENSP00000246662.

Structurei

3D structure databases

ProteinModelPortaliP35527.
SMRiP35527.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni1 – 152HeadAdd BLAST152
Regioni153 – 461RodAdd BLAST309
Regioni153 – 188Coil 1AAdd BLAST36
Regioni189 – 207Linker 1Add BLAST19
Regioni208 – 299Coil 1BAdd BLAST92
Regioni300 – 322Linker 12Add BLAST23
Regioni323 – 461Coil 2Add BLAST139
Regioni462 – 623TailAdd BLAST162

Compositional bias

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Compositional biasi15 – 26Poly-GlyAdd BLAST12

Sequence similaritiesi

Belongs to the intermediate filament family.Curated

Keywords - Domaini

Coiled coil

Phylogenomic databases

eggNOGiENOG410IEYG. Eukaryota.
ENOG4111C5Z. LUCA.
GeneTreeiENSGT00760000118808.
HOGENOMiHOG000230975.
HOVERGENiHBG013015.
InParanoidiP35527.
KOiK07604.
OMAiEMQYETL.
OrthoDBiEOG091G087I.
PhylomeDBiP35527.
TreeFamiTF332742.

Family and domain databases

InterProiIPR001664. IF.
IPR018039. Intermediate_filament_CS.
IPR002957. Keratin_I.
[Graphical view]
PANTHERiPTHR23239. PTHR23239. 2 hits.
PfamiPF00038. Filament. 1 hit.
[Graphical view]
PRINTSiPR01248. TYPE1KERATIN.
SMARTiSM01391. Filament. 1 hit.
[Graphical view]
PROSITEiPS00226. IF. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Complete.

P35527-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MSCRQFSSSY LSRSGGGGGG GLGSGGSIRS SYSRFSSSGG GGGGGRFSSS
60 70 80 90 100
SGYGGGSSRV CGRGGGGSFG YSYGGGSGGG FSASSLGGGF GGGSRGFGGA
110 120 130 140 150
SGGGYSSSGG FGGGFGGGSG GGFGGGYGSG FGGFGGFGGG AGGGDGGILT
160 170 180 190 200
ANEKSTMQEL NSRLASYLDK VQALEEANND LENKIQDWYD KKGPAAIQKN
210 220 230 240 250
YSPYYNTIDD LKDQIVDLTV GNNKTLLDID NTRMTLDDFR IKFEMEQNLR
260 270 280 290 300
QGVDADINGL RQVLDNLTME KSDLEMQYET LQEELMALKK NHKEEMSQLT
310 320 330 340 350
GQNSGDVNVE INVAPGKDLT KTLNDMRQEY EQLIAKNRKD IENQYETQIT
360 370 380 390 400
QIEHEVSSSG QEVQSSAKEV TQLRHGVQEL EIELQSQLSK KAALEKSLED
410 420 430 440 450
TKNRYCGQLQ MIQEQISNLE AQITDVRQEI ECQNQEYSLL LSIKMRLEKE
460 470 480 490 500
IETYHNLLEG GQEDFESSGA GKIGLGGRGG SGGSYGRGSR GGSGGSYGGG
510 520 530 540 550
GSGGGYGGGS GSRGGSGGSY GGGSGSGGGS GGGYGGGSGG GHSGGSGGGH
560 570 580 590 600
SGGSGGNYGG GSGSGGGSGG GYGGGSGSRG GSGGSHGGGS GFGGESGGSY
610 620
GGGEEASGSG GGYGGGSGKS SHS
Length:623
Mass (Da):62,064
Last modified:June 16, 2009 - v3
Checksum:i45C833749B63873D
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti12 – 13SR → T in AAC60619 (PubMed:7507869).Curated2
Sequence conflicti12 – 13SR → T in CAA52924 (PubMed:7512862).Curated2
Sequence conflicti41G → R in AAC60619 (PubMed:7507869).Curated1
Sequence conflicti41G → R in CAA82315 (PubMed:7507869).Curated1
Sequence conflicti41G → R in CAA52924 (PubMed:7512862).Curated1
Sequence conflicti134F → L in AAC60619 (PubMed:7507869).Curated1
Sequence conflicti134F → L in CAA82315 (PubMed:7507869).Curated1
Sequence conflicti134F → L in CAA52924 (PubMed:7512862).Curated1
Sequence conflicti157 – 170MQELN…SYLDK → HLGAGSTPITASQP in AAI21171 (PubMed:15489334).CuratedAdd BLAST14

Natural variant

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Natural variantiVAR_071977157M → K in EPPK. 1 PublicationCorresponds to variant rs59510579dbSNPEnsembl.1
Natural variantiVAR_036805157M → R in EPPK. 1 PublicationCorresponds to variant rs59510579dbSNPEnsembl.1
Natural variantiVAR_010499157M → T in EPPK. 2 PublicationsCorresponds to variant rs59510579dbSNPEnsembl.1
Natural variantiVAR_010500157M → V in EPPK. 3 PublicationsCorresponds to variant rs58597584dbSNPEnsembl.1
Natural variantiVAR_035438160L → F in EPPK; with knuckle pads. 1 PublicationCorresponds to variant rs28940896dbSNPEnsembl.1
Natural variantiVAR_010501160L → V in EPPK. 1 PublicationCorresponds to variant rs28940896dbSNPEnsembl.1
Natural variantiVAR_036806161N → H in EPPK. 2 PublicationsCorresponds to variant rs59296273dbSNPEnsembl.1
Natural variantiVAR_036807161N → I in EPPK. 2 PublicationsCorresponds to variant rs56707768dbSNPEnsembl.1
Natural variantiVAR_003822161N → K in EPPK. 1 PublicationCorresponds to variant rs57536312dbSNPEnsembl.1
Natural variantiVAR_010502161N → S in EPPK. 2 PublicationsCorresponds to variant rs56707768dbSNPEnsembl.1
Natural variantiVAR_010503161N → Y in EPPK. 1 PublicationCorresponds to variant rs59296273dbSNPEnsembl.1
Natural variantiVAR_036808163R → P in EPPK. 1 PublicationCorresponds to variant rs57758262dbSNPEnsembl.1
Natural variantiVAR_003823163R → Q in EPPK. 6 PublicationsCorresponds to variant rs57758262dbSNPEnsembl.1
Natural variantiVAR_003824163R → W in EPPK. 5 PublicationsCorresponds to variant rs59616921dbSNPEnsembl.1
Natural variantiVAR_036809167Y → WL in EPPK. 1
Natural variantiVAR_003825168L → S in EPPK. 1 PublicationCorresponds to variant rs61157095dbSNPEnsembl.1
Natural variantiVAR_035439171V → M in EPPK. 1 PublicationCorresponds to variant rs57019720dbSNPEnsembl.1
Natural variantiVAR_010504172Q → P in EPPK. 1 PublicationCorresponds to variant rs59878153dbSNPEnsembl.1
Natural variantiVAR_071978406C → R in EPPK. 1 PublicationCorresponds to variant rs77688767dbSNPEnsembl.1
Natural variantiVAR_071979454Y → H in EPPK. 1 PublicationCorresponds to variant rs267607420dbSNPEnsembl.1
Natural variantiVAR_036810458L → F in EPPK. 1 PublicationCorresponds to variant rs58120120dbSNPEnsembl.1
Natural variantiVAR_071980458L → P in EPPK. 1 Publication1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
Z29074 mRNA. Translation: CAA82315.1.
S69510 mRNA. Translation: AAC60619.1.
X75015 Genomic DNA. Translation: CAA52924.1.
AC019349 Genomic DNA. No translation available.
AB001594 mRNA. Translation: BAA19418.1.
BC121170 mRNA. Translation: AAI21171.1.
CCDSiCCDS32654.1.
PIRiI37984.
RefSeqiNP_000217.2. NM_000226.3.
UniGeneiHs.654569.

Genome annotation databases

EnsembliENST00000246662; ENSP00000246662; ENSG00000171403.
GeneIDi3857.
KEGGihsa:3857.
UCSCiuc002hxe.5. human.

Cross-referencesi

Web resourcesi

Human Intermediate Filament Mutation Database

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
Z29074 mRNA. Translation: CAA82315.1.
S69510 mRNA. Translation: AAC60619.1.
X75015 Genomic DNA. Translation: CAA52924.1.
AC019349 Genomic DNA. No translation available.
AB001594 mRNA. Translation: BAA19418.1.
BC121170 mRNA. Translation: AAI21171.1.
CCDSiCCDS32654.1.
PIRiI37984.
RefSeqiNP_000217.2. NM_000226.3.
UniGeneiHs.654569.

3D structure databases

ProteinModelPortaliP35527.
SMRiP35527.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi110055. 45 interactors.
IntActiP35527. 19 interactors.
MINTiMINT-4998976.
STRINGi9606.ENSP00000246662.

PTM databases

iPTMnetiP35527.
PhosphoSitePlusiP35527.
SwissPalmiP35527.

Polymorphism and mutation databases

BioMutaiKRT9.
DMDMi239938886.

2D gel databases

DOSAC-COBS-2DPAGEP35527.

Proteomic databases

EPDiP35527.
PaxDbiP35527.
PeptideAtlasiP35527.
PRIDEiP35527.
TopDownProteomicsiP35527.

Protocols and materials databases

DNASUi3857.
Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000246662; ENSP00000246662; ENSG00000171403.
GeneIDi3857.
KEGGihsa:3857.
UCSCiuc002hxe.5. human.

Organism-specific databases

CTDi3857.
DisGeNETi3857.
GeneCardsiKRT9.
H-InvDBHIX0039018.
HGNCiHGNC:6447. KRT9.
HPAiHPA007261.
HPA009673.
MalaCardsiKRT9.
MIMi144200. phenotype.
149100. phenotype.
607606. gene.
neXtProtiNX_P35527.
OpenTargetsiENSG00000171403.
Orphaneti2199. Epidermolytic palmoplantar keratoderma.
PharmGKBiPA30235.
GenAtlasiSearch...

Phylogenomic databases

eggNOGiENOG410IEYG. Eukaryota.
ENOG4111C5Z. LUCA.
GeneTreeiENSGT00760000118808.
HOGENOMiHOG000230975.
HOVERGENiHBG013015.
InParanoidiP35527.
KOiK07604.
OMAiEMQYETL.
OrthoDBiEOG091G087I.
PhylomeDBiP35527.
TreeFamiTF332742.

Enzyme and pathway databases

BioCyciZFISH:ENSG00000171403-MONOMER.
ReactomeiR-HSA-6805567. Keratinization.
R-HSA-6809371. Formation of the cornified envelope.

Miscellaneous databases

GeneWikiiKeratin_9.
GenomeRNAii3857.
PROiP35527.
SOURCEiSearch...

Gene expression databases

BgeeiENSG00000171403.
CleanExiHS_KRT9.
ExpressionAtlasiP35527. baseline and differential.
GenevisibleiP35527. HS.

Family and domain databases

InterProiIPR001664. IF.
IPR018039. Intermediate_filament_CS.
IPR002957. Keratin_I.
[Graphical view]
PANTHERiPTHR23239. PTHR23239. 2 hits.
PfamiPF00038. Filament. 1 hit.
[Graphical view]
PRINTSiPR01248. TYPE1KERATIN.
SMARTiSM01391. Filament. 1 hit.
[Graphical view]
PROSITEiPS00226. IF. 1 hit.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiK1C9_HUMAN
AccessioniPrimary (citable) accession number: P35527
Secondary accession number(s): O00109, Q0IJ47, Q14665
Entry historyi
Integrated into UniProtKB/Swiss-Prot: June 1, 1994
Last sequence update: June 16, 2009
Last modified: November 30, 2016
This is version 172 of the entry and version 3 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program
DisclaimerAny medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care.

Miscellaneousi

Miscellaneous

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

Caution

Was originally thought to be a 60 kDa chain of placental scatter protein.1 Publication

Keywords - Technical termi

Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. Human chromosome 17
    Human chromosome 17: entries, gene names and cross-references to MIM
  2. Human entries with polymorphisms or disease mutations
    List of human entries with polymorphisms or disease mutations
  3. Human polymorphisms and disease mutations
    Index of human polymorphisms and disease mutations
  4. MIM cross-references
    Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot
  5. 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.