Seroatlas · Human Serome Atlas

HAP1

Huntingtin-associated protein 1

Also known as: HAP1_HUMAN, HAP2, hHLP1, HIP5, HLP

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

Protein identityUniProt · HPA

UniProt accession: P54257
Gene: HAP1
Ensembl: ENSG00000173805
Chromosome: 17
Canonical length: 671 aa
Protein class: Predicted intracellular proteins
Subcellular location: Nucleoli,Cytosol

OverviewNCBI Gene

Huntington's disease (HD), a neurodegenerative disorder characterized by loss of striatal neurons, is caused by an expansion of a polyglutamine tract in the HD protein huntingtin. This gene encodes a protein that interacts with huntingtin, with two cytoskeletal proteins (dynactin and pericentriolar autoantigen protein 1), and with a hepatocyte growth factor-regulated tyrosine kinase substrate. The interactions with cytoskeletal proteins and a kinase substrate suggest a role for this protein in vesicular trafficking or organelle transport. Several alternatively spliced transcript variants encoding different isoforms have been described for this gene. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

671 residues, UniProt reviewed canonical sequence.

>P54257|HAP1
     1  MRPKRLGRCC AGSRLGPGDP AALTCAPSPS ASPAPEPSAQ PQARGTGQRV GSRATSGSQF
    61  LSEARTGARP ASEAGAKAGA RRPSAFSAIQ GDVRSMPDNS DAPWTRFVFQ GPFGSRATGR
   121  GTGKAAGIWK TPAAYVGRRP GVSGPERAAF IRELEEALCP NLPPPVKKIT QEDVKVMLYL
   181  LEELLPPVWE SVTYGMVLQR ERDLNTAARI GQSLVKQNSV LMEENSKLEA LLGSAKEEIL
   241  YLRHQVNLRD ELLQLYSDSD EEDEDEEEEE EEKEAEEEQE EEEAEEDLQC AHPCDAPKLI
   301  SQEALLHQHH CPQLEALQEK LRLLEEENHQ LREEASQLDT LEDEEQMLIL ECVEQFSEAS
   361  QQMAELSEVL VLRLENYERQ QQEVARLQAQ VLKLQQRCRM YGAETEKLQK QLASEKEIQM
   421  QLQEESVWVG SQLQDLREKY MDCGGMLIEM QEEVKTLRQQ PPVSTGSATH YPYSVPLETL
   481  PGFQETLAEE LRTSLRRMIS DPVYFMERNY EMPRGDTSSL RYDFRYSEDR EQVRGFEAEE
   541  GLMLAADIMR GEDFTPAEEF VPQEELGAAK KVPAEEGVME EAELVSEETE GWEEVELELD
   601  EATRMNVVTS ALEASGLGPS HLDMNYVLQQ LANWQDAHYR RQLRWKMLQK GECPHGALPA
   661  ASRTSCRSSC R

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against HAP1 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): 0.61
Highest tissue expression: 42 nTPM

Expression across tissuesHPA

Tissue

hypothalamus: 42 nTPM
amygdala: 16 nTPM
basal ganglia: 15 nTPM
cerebral cortex: 14 nTPM
hippocampal formation: 12 nTPM
pituitary gland: 11 nTPM

Single-cell type

endometrial glandular cells: 155 nCPM
epididymal basal cells: 145 nCPM
tuft cells: 138 nCPM
epididymal clear cells: 65 nCPM
medullary thymic epithelial cells: 55 nCPM
syncytiotrophoblasts: 51 nCPM

Immune cell

basophil: 0.5 nTPM
neutrophil: 0.3 nTPM
NK-cell: 0.2 nTPM
naive B-cell: 0.1 nTPM
naive CD8 T-cell: 0.1 nTPM
plasmacytoid DC: 0.1 nTPM

Brain region

hypothalamus: 127 nTPM
medulla oblongata: 39 nTPM
thalamus: 38 nTPM
midbrain: 37 nTPM
pons: 34 nTPM
amygdala: 34 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): 1.64
gnomAD pLI: 0
gnomAD missense Z: -0.09
DepMap mean gene effect: -0.33
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

InteractionsUniProt · HPA

Protein binding partners of HAP1 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 HAP1 as an antibody target. Whether an autoantibody or antibody against HAP1 could matter depends on whether native HAP1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

HAP1 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.

Source-annotated serology context

The source annotations explicitly mention antibody, autoantibody, autoantigen, or autoimmune context. This is biological context, not study-specific reactivity.

This gene encodes a protein that interacts with huntingtin, with two cytoskeletal proteins (dynactin and pericentriolar autoantigen protein 1), and with a hepatocyte growth factor-regulated tyrosine kinase substrate.

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