Seroatlas · Human Serome Atlas

SLC44A3

Choline transporter-like protein 3

Also known as: CTL3, CTL3_HUMAN, MGC45474

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

Protein identityUniProt · HPA

UniProt accession: Q8N4M1
Gene: SLC44A3
Ensembl: ENSG00000143036
Chromosome: 1
Canonical length: 653 aa
Protein class: Cancer-related genes, Metabolic proteins, Predicted intracellular proteins, Predicted membrane proteins, Transporters

OverviewNCBI Gene

Predicted to enable transmembrane transporter activity. Predicted to be involved in transmembrane transport. Predicted to be located in plasma membrane. Predicted to be active in membrane. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

653 residues, UniProt reviewed canonical sequence.

>Q8N4M1|SLC44A3
     1  MHCLGAEYLV SAEGAPRQRE WRPQIYRKCT DTAWLFLFFL FWTGLVFIMG YSVVAGAAGR
    61  LLFGYDSFGN MCGKKNSPVE GAPLSGQDMT LKKHVFFMNS CNLEVKGTQL NRMALCVSNC
   121  PEEQLDSLEE VQFFANTSGS FLCVYSLNSF NYTHSPKADS LCPRLPVPPS KSFPLFNRCV
   181  PQTPECYSLF ASVLINDVDT LHRILSGIMS GRDTILGLCI LALALSLAMM FTFRFITTLL
   241  VHIFISLVIL GLLFVCGVLW WLYYDYTNDL SIELDTEREN MKCVLGFAIV STGITAVLLV
   301  LIFVLRKRIK LTVELFQITN KAISSAPFLL FQPLWTFAIL IFFWVLWVAV LLSLGTAGAA
   361  QVMEGGQVEY KPLSGIRYMW SYHLIGLIWT SEFILACQQM TIAGAVVTCY FNRSKNDPPD
   421  HPILSSLSIL FFYHQGTVVK GSFLISVVRI PRIIVMYMQN ALKEQQHGAL SRYLFRCCYC
   481  CFWCLDKYLL HLNQNAYTTT AINGTDFCTS AKDAFKILSK NSSHFTSINC FGDFIIFLGK
   541  VLVVCFTVFG GLMAFNYNRA FQVWAVPLLL VAFFAYLVAH SFLSVFETVL DALFLCFAVD
   601  LETNDGSSEK PYFMDQEFLS FVKRSNKLNN ARAQQDKHSL RNEEGTELQA IVR

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SLC44A3 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: Cell surface
Secreted: No
Transmembrane segments: 8
Mean surface accessibility (rSASA): 0.28
Highest tissue expression: 33 nTPM

Expression across tissuesHPA

Tissue

rectum: 33 nTPM
colon: 30 nTPM
stomach: 28 nTPM
kidney: 27 nTPM
small intestine: 26 nTPM
pancreas: 26 nTPM

Single-cell type

somatotrophs: 282 nCPM
esophageal apical cells: 258 nCPM
thyrotrophs: 198 nCPM
distal convoluted tubule cells: 141 nCPM
tuft cells: 127 nCPM
enteric stem cells: 122 nCPM

Immune cell

MAIT T-cell: 1.8 nTPM
memory CD8 T-cell: 0.3 nTPM
memory CD4 T-cell: 0.2 nTPM
basophil: 0 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM

Brain region

medulla oblongata: 23 nTPM
white matter: 17 nTPM
cerebellum: 16 nTPM
spinal cord: 16 nTPM
hypothalamus: 15 nTPM
midbrain: 14 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): 1.47
gnomAD pLI: 0
gnomAD missense Z: 0.99
DepMap mean gene effect: -0.22
DepMap dependency class: selective

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

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SLC44A3 as an antibody target. Whether an autoantibody or antibody against SLC44A3 could matter depends on whether native SLC44A3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SLC44A3 is annotated at the cell surface, where native SLC44A3 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label SLC44A3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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