KRTAP20-2

Summary

KRTAP20-2 (keratin associated protein 20-2, HGNC:18944) is a protein-coding gene on chromosome 21q22.11, encoding Keratin-associated protein 20-2 (Q3LI61). In the hair cortex, hair keratin intermediate filaments are embedded in an interfilamentous matrix, consisting of hair keratin-associated proteins (KRTAP), which are essential for the formation of a rigid and resistant hair shaft through their extensive disulfide bond cross-link….

Predicted to be located in cytosol.

Source: NCBI Gene 337976 — RefSeq curated summary.

At a glance

• Clinical variants (ClinVar): 5 total
• MANE Select transcript: NM_181616

Identifiers

Gene identifiers

Field	Value
HGNC ID	HGNC:18944
Approved symbol	KRTAP20-2
Name	keratin associated protein 20-2
Location	21q22.11
Locus type	gene with protein product
Status	Approved
Aliases	KAP20.2
Ensembl gene	ENSG00000184032
Ensembl biotype	protein_coding
Entrez	337976

Gene structure

Transcript identifiers

Ensembl transcripts: 1 — 1 protein_coding

ENST00000330798

RefSeq mRNA: 1 — MANE Select: NM_181616 NM_181616

CCDS: CCDS13604

Canonical transcript exons

ENST00000330798 — 1 exons

Exon	Start	End
ENSE00001293539	30635206	30635619

Expression profiles

Bgee: expression breadth broad, 19 present calls, max score 81.65.

FANTOM5 (CAGE): breadth tissue_specific, TPM avg 0.0085 / max 7.7505, expressed in 4 samples.

FANTOM5 promoters (1 alternative TSS)

Promoter ID	TPM avg	Samples expressed
188781	0.0085	4

Top tissues by expression

107 total, by Bgee expression score (0-100, higher = more expressed):

Tissue	Anatomy ID	Expression score	Quality
male germ line stem cell (sensu Vertebrata) in testis	CL:0000089 ∩ UBERON:0000473	81.65	silver quality
primordial germ cell in gonad	CL:0000670 ∩ UBERON:0000991	67.39	gold quality
colonic epithelium	UBERON:0000397	37.20	gold quality
ventricular zone	UBERON:0003053	36.48	gold quality
cortical plate	UBERON:0005343	36.47	gold quality
bone marrow cell	CL:0002092	36.16	gold quality
ganglionic eminence	UBERON:0004023	35.49	gold quality
skeletal muscle tissue	UBERON:0001134	33.38	gold quality
skin of leg	UBERON:0001511	32.92	gold quality
hindlimb stylopod muscle	UBERON:0004252	32.15	gold quality
zone of skin	UBERON:0000014	32.03	gold quality
bone marrow	UBERON:0002371	31.74	gold quality
muscle tissue	UBERON:0002385	31.06	gold quality
sural nerve	UBERON:0015488	30.93	gold quality
skin of abdomen	UBERON:0001416	30.05	gold quality
stromal cell of endometrium	CL:0002255	29.87	gold quality
duodenum	UBERON:0002114	28.14	gold quality
liver	UBERON:0002107	28.04	gold quality
lymph node	UBERON:0000029	27.57	gold quality
islet of Langerhans	UBERON:0000006	27.18	gold quality
tonsil	UBERON:0002372	27.05	gold quality
vermiform appendix	UBERON:0001154	26.42	gold quality
gall bladder	UBERON:0002110	25.98	gold quality
blood	UBERON:0000178	25.94	gold quality
olfactory segment of nasal mucosa	UBERON:0005386	25.89	gold quality
placenta	UBERON:0001987	25.81	gold quality
leukocyte	CL:0000738	25.73	gold quality
urinary bladder	UBERON:0001255	25.72	gold quality
monocyte	CL:0000576	25.55	gold quality
pancreas	UBERON:0001264	24.84	gold quality

Single-cell (SCXA)

Detected in 1 experiment(s), a significant marker in 0.

Experiment	Marker?	Max mean expression
E-ANND-3	no	0.82

Regulation

Is transcription factor: no

Cross-species orthologs

0 orthologs

Protein

Protein identifiers

Keratin-associated protein 20-2 — Q3LI61 (reviewed: Q3LI61)

All UniProt accessions (1): Q3LI61

UniProt curated annotations — full annotation on UniProt →

Function. In the hair cortex, hair keratin intermediate filaments are embedded in an interfilamentous matrix, consisting of hair keratin-associated proteins (KRTAP), which are essential for the formation of a rigid and resistant hair shaft through their extensive disulfide bond cross-linking with abundant cysteine residues of hair keratins. The matrix proteins include the high-sulfur and high-glycine-tyrosine keratins.

Subunit / interactions. Interacts with hair keratins.

Similarity. Belongs to the KRTAP type 20 family.

RefSeq proteins (1): NP_853647* (*=MANE)

Domains & families (InterPro)

ID	Name	Type
IPR021743	KRTAP_type8/19/20/21/22	Family
IPR052878	KRTAP_matrix	Family

Pfam: PF11759

UniProt features (4 total): sequence variant 3, chain 1

Structure

Experimental structures (PDB)

0 structures.

Predicted structure (AlphaFold)

Model	pLDDT	Fraction very-high
AF-Q3LI61-F1	45.16	0.00

Function

Pathways and Gene Ontology

Reactome pathways

2 pathways

ID	Pathway
R-HSA-6805567	Keratinization
R-HSA-1266738	Developmental Biology

MSigDB gene sets: 27 (showing top): chr21q22, GOCC_INTERMEDIATE_FILAMENT_CYTOSKELETON, GOCC_SUPRAMOLECULAR_COMPLEX, GOCC_POLYMERIC_CYTOSKELETAL_FIBER, REACTOME_KERATINIZATION, GSE5503_MLN_DC_VS_SPLEEN_DC_ACTIVATED_ALLOGENIC_TCELL_DN, GOCC_SUPRAMOLECULAR_POLYMER, TATA_01, GSE17721_PAM3CSK4_VS_CPG_12H_BMDC_DN, GSE17721_PAM3CSK4_VS_GADIQUIMOD_0.5H_BMDC_UP, NOTCH3_TARGET_GENES, GSE24142_EARLY_THYMIC_PROGENITOR_VS_DN2_THYMOCYTE_FETAL_DN, GSE7460_FOXP3_MUT_VS_HET_ACT_TCONV_UP, GSE7460_CTRL_VS_FOXP3_OVEREXPR_TCONV_1_UP, GSE8384_CTRL_VS_B_ABORTUS_4H_MAC_CELL_LINE_DN

GO Biological Process (0):

GO Molecular Function (0):

GO Cellular Component (2): cytosol (GO:0005829), intermediate filament (GO:0005882)

Reactome top-level categories

Rollup of top-1 pathways:

Category	Pathways
Developmental Biology	1

GO top-level categories

Rollup of top GO terms by namespace:

Category	Terms
cytoplasm	1
cellular anatomical structure	1
intermediate filament cytoskeleton	1
polymeric cytoskeletal fiber	1

Protein interactions and networks

STRING

106 interactions, top by confidence (×1000):

Protein A	Protein B	Partner UniProt	Score
KRTAP20-2	KRTAP22-1	Q3MIV0	877
KRTAP20-2	SCYGR1	A0A286YEY9	870
KRTAP20-2	KRTAP15-1	Q3LI76	840
KRTAP20-2	KRTAP24-1	Q3LI83	830
KRTAP20-2	KRTAP13-3	Q3SY46	792
KRTAP20-2	KRTAP6-3	Q3LI67	791
KRTAP20-2	KRTAP26-1	Q6PEX3	791
KRTAP20-2	KRTAP6-2	Q3LI66	783
KRTAP20-2	KRTAP6-1	Q3LI64	782
KRTAP20-2	KRTAP7-1	Q8IUC3	776
KRTAP20-2	KRTAP13-1	Q8IUC0	772
KRTAP20-2	KRTAP8-1	Q8IUC2	767
KRTAP20-2	KRTAP27-1	Q3LI81	720
KRTAP20-2	KRTAP11-1	Q8IUC1	678
KRTAP20-2	KRTAP21-1	Q3LI58	631

IntAct

0 interactions, top by confidence:

ESM2 similar proteins: H2A0M6, O08632, O08633, O08640, P02448, P04459, P05685, P08826, P25692, P82170, P83358, Q02957, Q02958, Q28580, Q3LHN2, Q3LI54, Q3LI58, Q3LI59, Q3LI60, Q3LI61, Q3LI63, Q3LI64, Q3LI66, Q3LI67, Q3LI68, Q3LI70, Q3LI72, Q3LI73, Q3LI77, Q3MIV0, Q3SYF9, Q4W7G7, Q4W7G8, Q4W7G9, Q4W7H0, Q4W7H1, Q6F4C6, Q6R645, Q7Z4W3, Q8C1I6

Diamond homologs: Q3LI61, Q3LI63, Q3LI72, Q3SYF9, Q3LI70, Q3LI73, Q7Z4W3, Q8IUB9, Q99NG9

SIGNOR signaling

0 interactions.

Disease & clinical

Clinical variants and AI predictions

ClinVar

5 variants total. Per-class counts are floors (≥ shown; pagination cap):

Classification	Count (floor)
Pathogenic	0
Likely pathogenic	0
Uncertain significance	5
Likely benign	0
Benign	0

Top pathogenic / likely-pathogenic (0)

SpliceAI

83 predictions. Top by Δscore:

Variant	Effect	Δscore
21:30635291:G:GA	donor_gain	0.8400
21:30635290:T:TA	donor_gain	0.8000
21:30635309:G:GT	donor_gain	0.7800
21:30635292:G:GG	donor_gain	0.7500
21:30635437:A:G	donor_gain	0.6600
21:30635326:C:G	donor_gain	0.6400
21:30635269:C:CG	donor_gain	0.6300
21:30635324:G:GA	donor_gain	0.6000
21:30635433:G:GT	donor_gain	0.5900
21:30635398:C:G	donor_gain	0.5800
21:30635292:GTC:G	donor_gain	0.5500
21:30635293:TCT:T	donor_gain	0.5500
21:30635305:C:G	donor_gain	0.5500
21:30635462:G:GT	donor_gain	0.5500
21:30635342:G:GA	donor_gain	0.5300
21:30635304:GC:G	donor_gain	0.5200
21:30635323:T:TA	donor_gain	0.5000
21:30635396:G:GA	donor_gain	0.5000
21:30635433:G:T	donor_gain	0.4900
21:30635289:G:GT	donor_gain	0.4700
21:30635559:A:G	acceptor_gain	0.4700
21:30635428:C:G	donor_gain	0.4600
21:30635355:GC:G	donor_gain	0.4500
21:30635538:G:GG	donor_gain	0.4500
21:30635395:T:TA	donor_gain	0.4400
21:30635445:C:A	donor_gain	0.4400
21:30635294:C:A	donor_gain	0.4300
21:30635356:C:G	donor_gain	0.4300
21:30635361:G:GT	donor_gain	0.4300
21:30635487:G:GA	donor_gain	0.4300

AlphaMissense

394 scored. Top likely-pathogenic:

Variant	Protein change	am_pathogenicity
21:30635453:T:C	F64L	0.866
21:30635455:C:A	F64L	0.866
21:30635455:C:G	F64L	0.866
21:30635456:T:G	Y65D	0.645

dbSNP variants (sampled 300 via entrez): RS1000305313 (21:30635540 A>T), RS1001039903 (21:30634172 T>G), RS1002477311 (21:30635215 G>A), RS1004296604 (21:30634468 G>A), RS1004588494 (21:30633390 A>G), RS1004648859 (21:30634649 A>C), RS1005709975 (21:30636010 G>T), RS1006968021 (21:30635618 C>G,T), RS1008396461 (21:30634222 G>A), RS1008910124 (21:30633861 T>G), RS1011896990 (21:30635062 A>T), RS1012014737 (21:30633418 T>C), RS1013160698 (21:30633455 T>C), RS1013879201 (21:30636101 C>T), RS1014308224 (21:30635203 G>A,T)

Disease associations

OMIM: gene `` | disease phenotypes:

GenCC curated gene-disease

Mondo (0):

Orphanet (0):

HPO phenotypes

0 total (0 of 0 shown, HPO-id order):

GWAS associations

0 associations (top):

Drugs & pharmacology

Drug and pharmacology data

Is drug target: no

PharmGKB: 1 entry (VIP=true, CPIC=false)

CTD chemical–gene interactions

3 total (human), top 3 by PubMed support.

Chemical	Actions (top 5)	PubMed papers
bisphenol A	affects cotreatment, decreases methylation, increases methylation	1
Fulvestrant	decreases methylation, affects cotreatment	1
Estradiol	affects expression	1

Clinical trials (associated diseases)

0 trials via MONDO — disease-level, not drug-specific.