Huntingtin-associated protein 1

Huntingtin-associated protein 1 (HAP1) is a protein that in humans is encoded by the HAP1 gene. It is known to have a strong interaction with huntingtin, the protein mutated in Huntington's disease.

Function[edit | edit source]

HAP1 is involved in intracellular trafficking and has been shown to regulate the transport of various cargoes such as brain-derived neurotrophic factor (BDNF), glucose transporter type 4 (GLUT4), and epidermal growth factor receptor (EGFR). It is also involved in the regulation of autophagy, a process that degrades and recycles cellular components.

Structure[edit | edit source]

The HAP1 protein consists of several domains, including a tetratricopeptide repeat (TPR) domain, a coiled-coil domain, and a PDZ domain. The TPR domain is involved in protein-protein interactions, while the coiled-coil domain is thought to be involved in the formation of protein complexes. The PDZ domain is involved in the binding of HAP1 to other proteins.

Clinical significance[edit | edit source]

Alterations in the function or expression of HAP1 have been implicated in several diseases, including Huntington's disease, Alzheimer's disease, and cancer. In Huntington's disease, the interaction between HAP1 and huntingtin is disrupted, leading to neuronal dysfunction and death. In Alzheimer's disease, HAP1 has been shown to regulate the trafficking of amyloid precursor protein, which is involved in the formation of amyloid plaques, a hallmark of the disease. In cancer, overexpression of HAP1 has been associated with increased cell proliferation and survival.