Seroatlas · Human Serome Atlas

HHLA1

HERV-H LTR-associating protein 1

Also known as: HHLA1_HUMAN, PLA2L

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

Protein identityUniProt · HPA

UniProt accession: C9JL84
Gene: HHLA1
Ensembl: ENSG00000132297
Chromosome: 8
Canonical length: 531 aa
Protein class: Predicted secreted proteins
Secretome location: Secreted - unknown location

OverviewNCBI Gene

Predicted to be located in extracellular region. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

531 residues, UniProt reviewed canonical sequence.

>C9JL84|HHLA1
     1  MLGFLSRGPS MKLCMGLACV LSLWNTVSGI KGEAKKEKGM TFLPTTVSGL REEERKEKGV
    61  AFLATTELPA RSIDLSALNL TELVNGMLSR ALKDSKKFFS LLSVTSYSSF AFHKFSVAVY
   121  NISNLKTVDP AKFPTRYCYC LNNRTNDLSD FTALLVDIIG NSTSYLTEIF KSTSILSVNQ
   181  SNESDCIFIC VMTGKSGRNL SDFWEIEEKY PIINYTFTSG LSGVLGAATR GTARTSKPTT
   241  KSQKTLPSTS PGHWTQSTPW ASALRSSPWT ETAAPSETEE TLNTGRPPEL PARATATWFS
   301  ASHTLPALAT RRVARTQWLT ADRQTWASIS SVPWAQTISE KKPGGSLWET RSSPPTTAGT
   361  EEAMNTTSLL APAAEIMATP GSPSQASPTL GAFTHGTQTP SPTKATAPRY PQTGDLSAEW
   421  PFTAGEEPVL VPRPHQVSRC PQPLFKVGAM AAAPLTLAIQ RLNPCLMELC QFFQQCLCMS
   481  QRSPRTEDMR YCLEYYSWFL KNATYICQRV KRVSHSHTLK QKCLENICKS V

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against HHLA1 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): 0.57
Highest tissue expression: 0 nTPM

Expression across tissuesHPA

Tissue

adipose tissue: 0 nTPM
adrenal gland: 0 nTPM
amygdala: 0 nTPM
appendix: 0 nTPM
basal ganglia: 0 nTPM
blood vessel: 0 nTPM

Single-cell type

other brain neurons: 2.3 nCPM
melanocytes: 2 nCPM
brain inhibitory neurons: 1.4 nCPM
brain excitatory neurons: 1.1 nCPM
mucous neck cells: 0.8 nCPM
alveolar cells type 2: 0.5 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

midbrain: 0.6 nTPM
thalamus: 0.5 nTPM
cerebral cortex: 0.4 nTPM
hypothalamus: 0.3 nTPM
pons: 0.3 nTPM
basal ganglia: 0.2 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about HHLA1.

Disease | ImmuneIEDB

Conditions an epitope on HHLA1 was assayed in.

human immunodeficiency virus infectious disease T cell

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): 1.22
gnomAD pLI: 0
gnomAD missense Z: 0.71

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

Cellular components

extracellular region

Protein domainsUniProt · Pfam · InterPro

HERV-H LTR-associating protein 1

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads HHLA1 as an antibody target. Whether an autoantibody or antibody against HHLA1 could matter depends on whether native HHLA1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

HHLA1 is annotated as secreted, so native HHLA1 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 HHLA1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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