HAP1 Antibody, Biotin conjugated

HAP1, initially identified as a neuronal protein, exhibits specific binding to huntingtin (HTT). This interaction is enhanced by expanded polyglutamine repeats within HTT, potentially influencing HAP1's functional properties. Both HTT and HAP1 are implicated in intracellular trafficking, with HAP1 hypothesized to link HTT to motor proteins and/or transported cargo. HAP1 plays a role in neuronal and axonal vesicular transport, facilitating movement from early to late endocytic compartments and promoting neurite outgrowth. Mutant HTT can attenuate this vesicular transport function, mediated through interactions with microtubule-dependent transporters. HAP1 is involved in the axonal transport and activity-dependent secretion of brain-derived neurotrophic factor (BDNF), a process seemingly involving HTT, DCTN1, and a SORT1-containing complex. Furthermore, HAP1 participates in amyloid precursor protein (APP) trafficking, facilitating anterograde transport and membrane insertion, potentially reducing amyloid-beta processing. It also contributes to the synaptic delivery of GABA(A) receptors, a function dependent on the kinesin motor protein KIF5 and disrupted by HTT with expanded polyglutamine repeats. HAP1 regulates autophagosome motility by promoting efficient retrograde axonal transport. Its involvement extends to the regulation of membrane receptor recycling, degradation, and signal transduction, encompassing GABA(A) receptors, tyrosine kinase receptors, EGFR, IP3 receptor, and the androgen receptor. Additional proposed roles include the regulation of feeding behavior (via hypothalamic GABA(A) receptors), cerebellar and brainstem development (involving AHI1 and NTRK1/TrkA), postnatal neurogenesis (involving hypothalamic NTRK2/TrkB), and ITPR1/InsP3R1-mediated Ca²⁺ release (involving HTT and potentially the effects of mutant HTT). Through interactions with DCTN1/dynactin p150-glued and HTT, HAP1 participates in the cytoplasmic retention of REST in neurons. It may also be involved in ciliogenesis, exocytosis, and the formation of cytoplasmic inclusion bodies (STBs). In cases of anomalous TBP expression, HAP1 can sequester a subset of TBP into STBs, a process enhanced by expanded polyglutamine repeats within TBP. HAP1-containing STBs are suggested to play a protective role against neurodegeneration in Huntington's disease (HD) and spinocerebellar ataxia 17 (SCA17).

1. HAP1 expression in human gut endocrine cells. PMID: 27737633
2. HAP1 functions as a GKAP, specifically anchoring to the cGMP-dependent protein kinase isoform Ibeta; evidence supporting the role of anchoring proteins in regulating PKG spatiotemporal signaling. PMID: 25653285
3. The -141 T>G polymorphism, but not the 1349 T>G polymorphism, may offer protection against lung cancer. PMID: 25081373
4. HAP1 gene expression correlates with the radiosensitivity of breast cancer cells, suggesting a role in regulating cellular radiosensitivity. PMID: 25446120
5. HAP1 overexpression reduces in vitro cell growth in breast cancer cell lines. PMID: 23440330
6. No association found between the HAP1 T441M polymorphism and Huntington's disease age of onset. PMID: 22698993
7. HAP1 co-localizes and associates with APP in physiological conditions of mouse and human brain. PMID: 22731248
8. Wild-type HTT regulates ciliogenesis by interacting with pericentriolar material 1 protein (PCM1) via HAP1. PMID: 21985783
9. HAP1/stigmoid body interacts with normal ataxin-3 through the Josephin domain. PMID: 21386698
10. Sortilin stabilizes the proBDNF.HAP1 complex. PMID: 21357693
11. ADORA2A, but not HAP1 or OGG1, may influence Huntington's disease age of onset. PMID: 20512606
12. Review article on HAP1 function. PMID: 19262167
13. HAP1 may participate in axonal transport and activity-dependent release of pro-BDNF through interaction with the BDNF prodomain. PMID: 19996106
14. The combination of siRNA, the SB transposon, and an accurate transgenic mouse model allows for evaluation of approaches to prevent pathogenesis associated with mutant Htt expression. PMID: 15737634
15. Genetic and functional evidence suggests that the M441-HAP1 polymorphism modifies Huntington's disease age of onset. PMID: 18192679
16. REST/NRSF, dynactin p150(Glued), huntingtin, HAP1, and RILP form a complex involved in REST/NRSF nuclear translocation; HAP1 regulates REST/NRSF cellular localization in neurons. PMID: 18922795

HGNC: 4812

OMIM: 600947

KEGG: hsa:9001

UniGene: Hs.158300