HAP1

huntingtin associated protein 1

Ensembl:
ENSG00000173805
UniProt:
P54257
OMIM:
600947
Synonyms:
HAP2, HHLP1, HIP5, HLP

Cilia effects upon perturbation of HAP1

Cilia number / % ciliated:
Decreased cilia number
Loss-of-function effect:
Shorter cilia

Ciliogenesis screen results (3 screens)

  • Wheway et al. 2015 (siRNA) [siRNA]: Ciliogenesis Defect (z=-2.85) PMID:26167766
  • Breslow et al. 2018 (CRISPR) [CRISPR]: No Significant Effect PMID:29459680
  • Roosing et al. 2015 (siRNA) [siRNA]: No effect PMID:26595381

Phenotypes

Mouse phenotype:
increased blood urea nitrogen level, preweaning lethality, complete penetrance

Subcellular localization

basal body, nucleus

Functional category

  • Ciliary assembly/disassembly
  • Trafficking (BBSome, small GTPases, vesicular transport, ATPases)
  • Actin & cytoskeleton regulation
  • Neurogenesis & migration
  • Signaling (Hedgehog, GPCRs, ion channels)

Function

HTT-HAP1-dy ctin complex facilitates microtubule dependent vesicular transport. Regulates PCM1 trafficking and interacts with and huntingtin to control ciliogenesis. Depletion leads to dispersion of PCM1 from centrosomes and reduced ciliogenesis in cells. (21985783).

Model organism evidence

Mus musculus (2 references)

RESULTS: Mutations in AHI1 decrease cilia formation, alter its localization and stability, and change its binding to HAP1 and NPHP1.

Ciliogenesis is regulated by a huntingtin-HAP1-PCM1 pathway and is altered in Huntington disease.

PMIDs: 23532844, 21985783

Drosophila (1 reference)

Sperm cell elongation can proceed in the absence of an axoneme, suggesting that a mechanism besides intraflagellar transport emerged to sustain it.

PMIDs: 21549602