Seroatlas · Human Serome Atlas

SPAG16

Sperm-associated antigen 16 protein

Also known as: DKFZp666P1710, FLJ22724, PF20, SPG16_HUMAN, WDR29

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

Protein identityUniProt · HPA

UniProt accession: Q8N0X2
Gene: SPAG16
Ensembl: ENSG00000144451
Chromosome: 2
Canonical length: 631 aa
Protein class: Predicted intracellular proteins
Subcellular location: Vesicles,Plasma membrane,Cytosol,Acrosome,Equatorial segment

OverviewNCBI Gene

Cilia and flagella are comprised of a microtubular backbone, the axoneme, which is organized by the basal body and surrounded by plasma membrane. SPAG16 encodes 2 major proteins that associate with the axoneme of sperm tail and the nucleus of postmeiotic germ cells, respectively (Zhang et al., 2007 [PubMed 17699735]).[supplied by OMIM, Jul 2008]

Canonical amino-acid sequenceUniProt

631 residues, UniProt reviewed canonical sequence.

>Q8N0X2|SPAG16
     1  MAAQRGMPSS AVRVLEEALG MGLTAAGDAR DTADAVAAEG AYYLEQVTIT EASEDDYEYE
    61  EIPDDNFSIP EGEEDLAKAI QMAQEQATDT EILERKTVLP SKHAVPEVIE DFLCNFLIKM
   121  GMTRTLDCFQ SEWYELIQKG VTELRTVGNV PDVYTQIMLL ENENKNLKKD LKHYKQAADK
   181  AREDLLKIQK ERDFHRMHHK RIVQEKNKLI NDLKGLKLHY ASYEPTIRVL HEKHHTLLKE
   241  KMLTSLERDK VVGQISGLQE TLKKLQRGHS YHGPQIKVDH SREKENAPEG PTQKGLREAR
   301  EQNKCKTKMK GNTKDSEFPI DMQPNPNLNV SKESLSPAKF DYKLKNIFRL HELPVSCVSM
   361  QPHKDILVSC GEDRLWKVLG LPKCNVLLTG FGHTDWLSDC CFHPSGDKLA TSSGDTTVKL
   421  WDLCKGDCIL TFEGHSRAVW SCTWHSCGNF VASSSLDKTS KIWDVNSERC RCTLYGHTDS
   481  VNSIEFFPFS NTLLTSSADK TLSIWDARTG ICEQSLYGHM HSINDAIFDP RGHMIASCDA
   541  CGVTKLWDFR KLLPIVSIDI GPSPGNEVNF DSSGRVLAQA SGNGVIHLLD LKSGEIHKLM
   601  GHENEAHTVV FSHDGEILFS GGSDGTVRTW S

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SPAG16 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: Intracellular
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.4
Highest tissue expression: 64 nTPM

Expression across tissuesHPA

Tissue

spinal cord: 64 nTPM
midbrain: 54 nTPM
amygdala: 42 nTPM
testis: 41 nTPM
fallopian tube: 41 nTPM
hippocampal formation: 40 nTPM

Single-cell type

thyrotrophs: 2,509 nCPM
ependymal cells: 1,818 nCPM
respiratory ciliated cells: 1,623 nCPM
somatotrophs: 1,585 nCPM
lactotrophs: 1,281 nCPM
fallopian tube ciliated cells: 868 nCPM

Immune cell

NK-cell: 15 nTPM
MAIT T-cell: 12 nTPM
naive CD4 T-cell: 12 nTPM
naive CD8 T-cell: 10 nTPM
memory CD8 T-cell: 9.9 nTPM
T-reg: 9.3 nTPM

Brain region

spinal cord: 41 nTPM
white matter: 40 nTPM
midbrain: 38 nTPM
medulla oblongata: 38 nTPM
choroid plexus: 38 nTPM
hypothalamus: 37 nTPM

ReferencesPubMed · IEDB

Publications for SPAG16 from three distinct lines of evidence, kept separate because they answer different questions: whether antibodies are directed at the protein, whether a B-cell epitope has been mapped on it, and whether a T-cell epitope has. Each is labelled with its source.

Reference: AutoantibodyPubMed

2 publications

Sperm-associated antigen 16 is a novel target of the humoral autoimmune response in multiple sclerosis.
2014 · J Immunol · RCR 0.7 · 21 citations
Anti-SPAG16 antibodies in primary progressive multiple sclerosis are associated with an elevated progression index.
2016 · Eur J Neurol · RCR 0.5 · 13 citations

Sources: PubMed — antigen-level antibody evidence from a custom retrieval. Records matching a controlled set of autoantibody terms (the MeSH descriptors Autoantibodies and Autoantigens, with title and abstract term variants) were obtained through NCBI E-utilities, and their titles and abstracts parsed for constructions that direct an antibody at a named protein rather than for co-occurrence. Captured names were resolved against UniProt nomenclature and each antigen adjudicated individually against the source text. Bibliographic records from PubMed and MeSH, U.S. National Library of Medicine; citation metrics from NIH iCite (Hutchins et al., PLoS Biology 2016). Titles link to PubMed; abstracts are not reproduced here. The NLM does not endorse this analysis.

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): 1.71
gnomAD pLI: 0
gnomAD missense Z: -0.87
DepMap mean gene effect: 0.14
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of SPAG16 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SPAG16 as an antibody target. Whether an autoantibody or antibody against SPAG16 could matter depends on whether native SPAG16 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SPAG16 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label SPAG16 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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