KRTAP9-1

Summary

KRTAP9-1 (keratin associated protein 9-1, HGNC:18912) is a protein-coding gene on chromosome 17q21.2, encoding Keratin-associated protein 9-1 (A8MXZ3). 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 728318 — RefSeq curated summary.

At a glance

• Clinical variants (ClinVar): 43 total
• MANE Select transcript: NM_001190460

Identifiers

Gene identifiers

Field	Value
HGNC ID	HGNC:18912
Approved symbol	KRTAP9-1
Name	keratin associated protein 9-1
Location	17q21.2
Locus type	gene with protein product
Status	Approved
Aliases	KAP9.1
Ensembl gene	ENSG00000240542
Ensembl biotype	protein_coding
Entrez	728318

Gene structure

Transcript identifiers

Ensembl transcripts: 1 — 1 protein_coding

ENST00000398470

RefSeq mRNA: 1 — MANE Select: NM_001190460 NM_001190460

CCDS: CCDS56029

Canonical transcript exons

ENST00000398470 — 1 exons

Exon	Start	End
ENSE00001470849	41189887	41190639

Expression profiles

Bgee: expression breadth broad, 11 present calls, max score 46.51.

Top tissues by expression

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

Tissue	Anatomy ID	Expression score	Quality
granulocyte	CL:0000094	46.51	silver quality
sural nerve	UBERON:0015488	42.79	silver 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
hindlimb stylopod muscle	UBERON:0004252	32.15	gold quality
bone marrow	UBERON:0002371	31.74	gold quality
muscle tissue	UBERON:0002385	31.06	gold quality
stromal cell of endometrium	CL:0002255	29.87	gold quality
prefrontal cortex	UBERON:0000451	29.04	gold quality
monocyte	CL:0000576	28.40	gold quality
liver	UBERON:0002107	28.32	gold quality
duodenum	UBERON:0002114	28.14	gold quality
lymph node	UBERON:0000029	27.57	gold quality
tonsil	UBERON:0002372	27.05	gold quality
islet of Langerhans	UBERON:0000006	26.99	gold quality
vermiform appendix	UBERON:0001154	26.42	gold quality
blood	UBERON:0000178	26.41	gold quality
gall bladder	UBERON:0002110	25.98	gold quality
olfactory segment of nasal mucosa	UBERON:0005386	25.89	gold quality
placenta	UBERON:0001987	25.81	gold quality
muscle of leg	UBERON:0001383	25.15	gold quality
primary visual cortex	UBERON:0002436	24.61	gold quality
transverse colon	UBERON:0001157	24.29	gold quality
pancreas	UBERON:0001264	24.28	gold quality
left uterine tube	UBERON:0001303	24.16	gold quality
superior frontal gyrus	UBERON:0002661	24.08	gold quality

Single-cell (SCXA)

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

Experiment	Marker?	Max mean expression
E-ANND-3	no	0.98

Regulation

Is transcription factor: no

Cross-species orthologs

32 orthologs

Organism	Symbol	Gene ID
mus_musculus	Krtap5-2	ENSMUSG00000054759
mus_musculus	Krtap5-20	ENSMUSG00000056885
mus_musculus	Krtap10-4	ENSMUSG00000069582
mus_musculus	Krtap10-31	ENSMUSG00000071195
mus_musculus	Krtap9-5	ENSMUSG00000078255
mus_musculus	Krtap10-21	ENSMUSG00000094120
mus_musculus	Krtap10-27	ENSMUSG00000094913
mus_musculus	Krtap10-26	ENSMUSG00000095593
mus_musculus	Krtap10-25	ENSMUSG00000095721
mus_musculus	Krtap10-22	ENSMUSG00000095817
mus_musculus	Krtap10-33	ENSMUSG00000095970
mus_musculus	Krtap10-29	ENSMUSG00000096131
mus_musculus	Krtap10-34	ENSMUSG00000096380
mus_musculus	Krtap10-23	ENSMUSG00000096481
mus_musculus	Krtap5-26	ENSMUSG00000109859
mus_musculus	Krtap5-24	ENSMUSG00000110324
mus_musculus	Krtap10-24	ENSMUSG00000111915
mus_musculus	Krtap10-28	ENSMUSG00000112170
mus_musculus	Krtap10-10	ENSMUSG00000112223
mus_musculus	Krtap10-30	ENSMUSG00000112380
mus_musculus	Gm49918	ENSMUSG00000112600
mus_musculus	Krtap10-35	ENSMUSG00000112653
mus_musculus	Krtap10-32	ENSMUSG00000112864
rattus_norvegicus	Krtap10-8l1	ENSRNOG00000001218
rattus_norvegicus	Krtap5-8	ENSRNOG00000020131
rattus_norvegicus	Krtap10-10	ENSRNOG00000032530
rattus_norvegicus	Krtap10-9	ENSRNOG00000043302
rattus_norvegicus	Krtap10-1l1	ENSRNOG00000046538
rattus_norvegicus	AABR07006049.1	ENSRNOG00000046649
rattus_norvegicus	Krtap10-1	ENSRNOG00000047532
rattus_norvegicus	LOC120098854	ENSRNOG00000067436
rattus_norvegicus	Krtap10-10l2	ENSRNOG00000069553

Paralogs (47): KRTAP4-4 (ENSG00000171396), KRTAP9-7 (ENSG00000180386), KRTAP5-5 (ENSG00000185940), KRTAP12-1 (ENSG00000187175), KRTAP9-8 (ENSG00000187272), KRTAP10-8 (ENSG00000187766), KRTAP10-6 (ENSG00000188155), KRTAP1-1 (ENSG00000188581), KRTAP10-12 (ENSG00000189169), KRTAP4-3 (ENSG00000196156), KRTAP9-9 (ENSG00000198083), KRTAP4-6 (ENSG00000198090), KRTAP4-5 (ENSG00000198271), KRTAP4-1 (ENSG00000198443), KRTAP9-3 (ENSG00000204873), KRTAP4-8 (ENSG00000204880), KRTAP1-4 (ENSG00000204887), KRTAP12-3 (ENSG00000205439), KRTAP10-2 (ENSG00000205445), KRTAP5-6 (ENSG00000205864), KRTAP5-2 (ENSG00000205867), KRTAP16-1 (ENSG00000212657), KRTAP9-6 (ENSG00000212659), KRTAP4-11 (ENSG00000212721), KRTAP4-9 (ENSG00000212722), KRTAP2-3 (ENSG00000212724), KRTAP2-1 (ENSG00000212725), KRTAP10-3 (ENSG00000212935), KRTAP4-12 (ENSG00000213416), KRTAP2-4 (ENSG00000213417), KRTAP2-2 (ENSG00000214518), KRTAP10-4 (ENSG00000215454), KRTAP10-1 (ENSG00000215455), KRTAP10-9 (ENSG00000221837), KRTAP1-5 (ENSG00000221852), KRTAP10-10 (ENSG00000221859), KRTAP12-2 (ENSG00000221864), KRTAP1-3 (ENSG00000221880), KRTAP9-2 (ENSG00000239886), KRTAP4-7 (ENSG00000240871)

Protein

Protein identifiers

Keratin-associated protein 9-1 — A8MXZ3 (reviewed: A8MXZ3)

Alternative names: Keratin-associated protein 9-like 3

All UniProt accessions (1): A8MXZ3

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 9 family.

RefSeq proteins (1): NP_001177389* (*=MANE)

Domains & families (InterPro)

UniProt features (34 total): repeat 32, chain 1, region of interest 1

Structure

Experimental structures (PDB)

0 structures.

Predicted structure (AlphaFold)

Model	pLDDT	Fraction very-high
AF-A8MXZ3-F1	35.39	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: 8 (showing top): GOCC_INTERMEDIATE_FILAMENT_CYTOSKELETON, GOCC_KERATIN_FILAMENT, GOCC_SUPRAMOLECULAR_COMPLEX, GOCC_POLYMERIC_CYTOSKELETAL_FIBER, ZWANG_TRANSIENTLY_UP_BY_2ND_EGF_PULSE_ONLY, REACTOME_KERATINIZATION, GOCC_SUPRAMOLECULAR_POLYMER, chr17q21

GO Biological Process (0):

GO Molecular Function (0):

GO Cellular Component (3): cytosol (GO:0005829), keratin filament (GO:0045095), 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	1
intermediate filament cytoskeleton	1
polymeric cytoskeletal fiber	1

Protein interactions and networks

STRING

298 interactions, top by confidence (×1000):

Protein A	Protein B	Partner UniProt	Score
KRTAP9-1	KRTAP3-3	Q9BYR6	564
KRTAP9-1	KRTAP11-1	Q8IUC1	518
KRTAP9-1	NUTM2G	Q5VZR2	518
KRTAP9-1	OR1E2	P47887	507
KRTAP9-1	MROH8	Q9H579	505
KRTAP9-1	OR1D5	P58170	480
KRTAP9-1	OR3A2	P47893	477
KRTAP9-1	OR3A1	P47881	472
KRTAP9-1	KRTAP17-1	Q9BYP8	470
KRTAP9-1	MCRIP1	C9JLW8	435
KRTAP9-1	TMEM95	Q3KNT9	434
KRTAP9-1	KRT71	Q3SY84	421
KRTAP9-1	C17orf50	Q8WW18	413
KRTAP9-1	OR1A2	Q9Y585	410
KRTAP9-1	TMEM220	Q6QAJ8	400

IntAct

0 interactions, top by confidence:

BioGRID (1): KRTAP9-1 (Affinity Capture-MS)

ESM2 similar proteins: A5A6P5, A6QP35, A8MTY7, A8MVA2, A8MXZ3, O75690, P02438, P02441, P02442, P02443, P08131, P0C7H8, P26371, P59990, P59991, P60014, P60331, P60368, P60369, P60370, P60371, P60372, P60409, P60410, P60411, P60412, P60413, Q05B44, Q07627, Q3V2C1, Q6L8G4, Q6L8G8, Q6L8G9, Q6L8H2, Q701N4, Q8IUG1, Q9BQ66, Q9BYP9, Q9BYQ0, Q9BYQ2

SIGNOR signaling

0 interactions.

Disease & clinical

Clinical variants and AI predictions

ClinVar

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

Classification	Count (floor)
Pathogenic	0
Likely pathogenic	0
Uncertain significance	40
Likely benign	3
Benign	0

Top pathogenic / likely-pathogenic (0)

SpliceAI

116 predictions. Top by Δscore:

Variant	Effect	Δscore
17:41190185:GCT:G	donor_gain	0.8900
17:41190321:G:GT	donor_gain	0.8600
17:41190322:A:T	donor_gain	0.7300
17:41190075:G:GT	donor_gain	0.6400
17:41189958:G:GT	donor_gain	0.6200
17:41190636:C:G	donor_gain	0.6100
17:41190186:C:G	donor_gain	0.5900
17:41190503:A:AG	donor_gain	0.5700
17:41190158:G:GG	donor_gain	0.5400
17:41190276:G:GT	donor_gain	0.5400
17:41190161:G:A	donor_gain	0.5200
17:41190188:G:GG	donor_gain	0.5200
17:41190472:G:GA	donor_gain	0.5200
17:41190500:GCAA:G	donor_gain	0.5200
17:41190350:G:A	donor_gain	0.5100
17:41190157:T:G	donor_gain	0.5000
17:41190191:G:A	donor_gain	0.4900
17:41190187:T:G	donor_gain	0.4800
17:41190155:GCT:G	donor_gain	0.4700
17:41190347:G:GG	donor_gain	0.4700
17:41190513:C:G	donor_gain	0.4600
17:41190218:G:A	donor_gain	0.4500
17:41190564:G:GT	donor_gain	0.4500
17:41189975:C:G	donor_gain	0.4300
17:41190344:GCT:G	donor_gain	0.4300
17:41190470:GTG:G	donor_gain	0.4300
17:41190346:T:TG	donor_gain	0.4200
17:41190205:C:A	donor_gain	0.4100
17:41190214:T:G	donor_gain	0.4100
17:41190529:T:A	acceptor_gain	0.4100

AlphaMissense

1665 scored. Top likely-pathogenic:

Variant	Protein change	am_pathogenicity
17:41190271:T:C	F129L	0.619
17:41190273:C:A	F129L	0.619
17:41190273:C:G	F129L	0.619

dbSNP variants (sampled 300 via entrez): RS1001619271 (17:41189706 C>T), RS1001681128 (17:41188025 G>A), RS1001774289 (17:41188340 A>G), RS1001944292 (17:41189872 T>G), RS1002021992 (17:41189083 G>A,C), RS1002106372 (17:41189425 T>A), RS1002357849 (17:41188185 T>C), RS1002547180 (17:41191018 T>C,G), RS1003784711 (17:41190699 G>T), RS1004178868 (17:41189411 C>A,T), RS1004449564 (17:41190861 G>A), RS1004583582 (17:41190390 T>A,C), RS1004656832 (17:41189014 A>G,T), RS1008851234 (17:41188735 A>C), RS1009045885 (17:41189824 G>A)

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

2 total (human), top 2 by PubMed support.

Chemical	Actions (top 5)	PubMed papers
Cadmium	decreases expression, increases abundance	1
Cadmium Chloride	decreases expression, increases abundance	1

Clinical trials (associated diseases)

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