Seroatlas · Human Serome Atlas

COL21A1

Collagen alpha-1(XXI) chain

Also known as: COLA1_HUMAN

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession: Q96P44
Gene: COL21A1
Ensembl: ENSG00000124749
Chromosome: 6
Canonical length: 957 aa
Protein class: Predicted intracellular proteins, Predicted secreted proteins
Subcellular location: Cytosol
Secretome location: Secreted to extracellular matrix

OverviewNCBI Gene

This gene encodes the alpha chain of type XXI collagen, a member of the FACIT (fibril-associated collagens with interrupted helices) collagen family. Type XXI collagen is localized to tissues containing type I collagen and maintains the integrity of the extracellular matrix. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2016]

Canonical amino-acid sequenceUniProt

957 residues, UniProt reviewed canonical sequence.

>Q96P44|COL21A1
     1  MAHYITFLCM VLVLLLQNSV LAEDGEVRSS CRTAPTDLVF ILDGSYSVGP ENFEIVKKWL
    61  VNITKNFDIG PKFIQVGVVQ YSDYPVLEIP LGSYDSGEHL TAAVESILYL GGNTKTGKAI
   121  QFALDYLFAK SSRFLTKIAV VLTDGKSQDD VKDAAQAARD SKITLFAIGV GSETEDAELR
   181  AIANKPSSTY VFYVEDYIAI SKIREVMKQK LCEESVCPTR IPVAARDERG FDILLGLDVN
   241  KKVKKRIQLS PKKIKGYEVT SKVDLSELTS NVFPEGLPPS YVFVSTQRFK VKKIWDLWRI
   301  LTIDGRPQIA VTLNGVDKIL LFTTTSVING SQVVTFANPQ VKTLFDEGWH QIRLLVTEQD
   361  VTLYIDDQQI ENKPLHPVLG ILINGQTQIG KYSGKEETVQ FDVQKLRIYC DPEQNNRETA
   421  CEIPGFNGEC LNGPSDVGST PAPCICPPGK PGLQGPKGDP GLPGNPGYPG QPGQDGKPGY
   481  QGIAGTPGVP GSPGIQGARG LPGYKGEPGR DGDKGDRGLP GFPGLHGMPG SKGEMGAKGD
   541  KGSPGFYGKK GAKGEKGNAG FPGLPGPAGE PGRHGKDGLM GSPGFKGEAG SPGAPGQDGT
   601  RGEPGIPGFP GNRGLMGQKG EIGPPGQQGK KGAPGMPGLM GSNGSPGQPG TPGSKGSKGE
   661  PGIQGMPGAS GLKGEPGATG SPGEPGYMGL PGIQGKKGDK GNQGEKGIQG QKGENGRQGI
   721  PGQQGIQGHH GAKGERGEKG EPGVRGAIGS KGESGVDGLM GPAGPKGQPG DPGPQGPPGL
   781  DGKPGREFSE QFIRQVCTDV IRAQLPVLLQ SGRIRNCDHC LSQHGSPGIP GPPGPIGPEG
   841  PRGLPGLPGR DGVPGLVGVP GRPGVRGLKG LPGRNGEKGS QGFGYPGEQG PPGPPGPEGP
   901  PGISKEGPPG DPGLPGKDGD HGKPGIQGQP GPPGICDPSL CFSVIARRDP FRKGPNY

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against COL21A1 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability: Secreted
Secreted: Yes
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.45
Highest tissue expression: 29 nTPM

Expression across tissuesHPA

Tissue

blood vessel: 29 nTPM
placenta: 27 nTPM
cervix: 23 nTPM
endometrium: 12 nTPM
seminal vesicle: 10 nTPM
choroid plexus: 9.3 nTPM

Single-cell type

salivary ionocytes: 606 nCPM
pituitary stem cells: 493 nCPM
extravillous trophoblasts: 331 nCPM
ependymal cells: 321 nCPM
choroid plexus epithelial cells: 295 nCPM
respiratory ciliated cells: 292 nCPM

Immune cell

basophil: 0 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM
gdT-cell: 0 nTPM
intermediate monocyte: 0 nTPM
MAIT T-cell: 0 nTPM

Brain region

choroid plexus: 28 nTPM
midbrain: 18 nTPM
hypothalamus: 16 nTPM
thalamus: 12 nTPM
pons: 10 nTPM
basal ganglia: 10 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance): 1
gnomAD pLI: 0
gnomAD missense Z: 0.81
DepMap mean gene effect: -0.02
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads COL21A1 as an antibody target. Whether an autoantibody or antibody against COL21A1 could matter depends on whether native COL21A1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

COL21A1 is annotated as secreted, so native COL21A1 circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

The present source text does not explicitly label COL21A1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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