Aberrant role of ALK in tau proteinopathy through autophagosomal dysregulation.
Jisu ParkHyunwoo ChoiYoung Doo KimSeo-Hyun KimYoubin KimYoungdae GwonDong Young LeeHye-Kyung ParkWon Do HeoYong-Keun JungPublished in: Molecular psychiatry (2021)
Proteinopathy in neurodegenerative diseases is typically characterized by deteriorating activity of specific protein aggregates. In tauopathies, including Alzheimer's disease (AD), tau protein abnormally accumulates and induces dysfunction of the affected neurons. Despite active identification of tau modifications responsible for tau aggregation, a critical modulator inducing tau proteinopathy by affecting its protein degradation flux is not known. Here, we report that anaplastic lymphoma kinase (ALK), a receptor tyrosine kinase, is crucial for the tau-mediated AD pathology. ALK caused abnormal accumulation of highly phosphorylated tau in the somatodendritic region of neurons through its tyrosine kinase activity. ALK-induced LC3-positive axon swelling and loss of spine density, leading to tau-dependent neuronal degeneration. Notably, ALK activation in neurons impaired Stx17-dependent autophagosome maturation and this defect was reversed by a dominant-negative Grb2. In a Drosophila melanogaster model, transgenic flies neuronally expressing active Drosophila Alk exhibited the aggravated tau rough eye phenotype with retinal degeneration and shortened lifespan. In contrast, expression of kinase-dead Alk blocked these phenotypes. Consistent with the previous RNAseq analysis showing upregulation of ALK expression in AD [1], ALK levels were significantly elevated in the brains of AD patients showing autophagosomal defects. Injection of an ALK.Fc-lentivirus exacerbated memory impairment in 3xTg-AD mice. Conversely, pharmacologic inhibition of ALK activity with inhibitors reversed the memory impairment and tau accumulation in both 3xTg-AD and tauC3 (caspase-cleaved tau) transgenic mice. Together, we propose that aberrantly activated ALK is a bona fide mediator of tau proteinopathy that disrupts autophagosome maturation and causes tau accumulation and aggregation, leading to neuronal dysfunction in AD.
Keyphrases
- cerebrospinal fluid
- advanced non small cell lung cancer
- tyrosine kinase
- epidermal growth factor receptor
- poor prognosis
- spinal cord
- mass spectrometry
- magnetic resonance imaging
- binding protein
- magnetic resonance
- cell proliferation
- spinal cord injury
- insulin resistance
- end stage renal disease
- skeletal muscle
- drosophila melanogaster
- optical coherence tomography
- ejection fraction
- subarachnoid hemorrhage
- high fat diet induced
- peritoneal dialysis
- high glucose