Seroatlas · Human Serome Atlas

TTC39B

Tetratricopeptide repeat protein 39B

Also known as: C9orf52, FLJ33868, TT39B_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q5VTQ0
Gene: TTC39B
Ensembl: ENSG00000155158
Chromosome: 9
Canonical length: 682 aa
Protein class: Predicted intracellular proteins, Predicted membrane proteins
Subcellular location: Endoplasmic reticulum

OverviewNCBI Gene

Predicted to be involved in several processes, including cholesterol homeostasis; negative regulation of cholesterol storage; and regulation of cholesterol efflux. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

682 residues, UniProt reviewed canonical sequence.

>Q5VTQ0|TTC39B
     1  MDAVLACRLR GRGNRVAALR PRPRPGGSAG PSPFALLCAG LSPEPRAGVG SEFPAWFLGG
    61  SSQRRNMALL GSRAELEADE DVFEDALETI SISSHSDMAT SSLHFASCDT QQAPRQRGAS
   121  TVSSSSSTKV DLKSGLEECA VALNLFLSNK FTDALELLRP WAKESMYHAL GYSTIVVLQA
   181  VLTFEQQDIQ NGISAMKDAL QTCQKYRKKY TVVESFSSLL SRGSLEQLSE EEMHAEICYA
   241  ECLLQKAALT FVQDENMINF IKGGLKIRTS YQIYKECLSI LHEIQKNKLQ QEFFYEFEGG
   301  VKLGSGAFNL MLSLLPARII RLLEFIGFSG NRELGLLQLR EGASGRSMRS ALCCLTILAF
   361  HTYISLILGT GEVNVAEAER LLAPFLQQFP NGSLVLFYHA RIELLKGNLE EAQEVFQKCI
   421  SVQEEWKQFH HLCYWELMWI NVFQQNWMQA YYYSDLLCKE SKWSKATYVF LKAAILSMLP
   481  EEDVVATNEN VVTLFRQVDS LKQRIAGKSI PTEKFAVRKA RRYSASLPAP VKLILPALEM
   541  MYVWNGFSIV SKRKDLSENL LVTVEKAEAA LQSQNFNSFS VDDECLVKLL KGCCLKNLQR
   601  PLQAELCYNH VVESEKLLKY DHYLVPFTLF ELASLYKSQG EIDKAIKFLE TARNNYKDYS
   661  LESRLHFRIQ AALHLWRKPS SD

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against TTC39B 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: Unknown
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.31
Highest tissue expression: 9.1 nTPM

Expression across tissuesHPA

Tissue

skin: 9.1 nTPM
kidney: 8.9 nTPM
esophagus: 8.6 nTPM
cerebellum: 7.4 nTPM
colon: 6.7 nTPM
gallbladder: 6.7 nTPM

Single-cell type

thyrotrophs: 215 nCPM
renal collecting duct intercalated cells: 207 nCPM
proximal tubule cells: 186 nCPM
respiratory ionocytes: 160 nCPM
mast cells: 155 nCPM
esophageal apical cells: 149 nCPM

Immune cell

NK-cell: 8.1 nTPM
naive CD4 T-cell: 7.4 nTPM
memory CD8 T-cell: 6.5 nTPM
memory CD4 T-cell: 5.9 nTPM
T-reg: 5.4 nTPM
MAIT T-cell: 5.1 nTPM

Brain region

cerebellum: 33 nTPM
pons: 26 nTPM
cerebral cortex: 25 nTPM
medulla oblongata: 24 nTPM
thalamus: 21 nTPM
hypothalamus: 21 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): 0.97
gnomAD pLI: 0
gnomAD missense Z: -1.3
DepMap mean gene effect: 0.05
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of TTC39B in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

VAPB

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads TTC39B as an antibody target. Whether an autoantibody or antibody against TTC39B could matter depends on whether native TTC39B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

TTC39B 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 TTC39B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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