GSK3β Impairs KIF1A Transport in a Cellular Model of Alzheimer’s Disease but Does Not Regulate Motor Motility at S402

Abstract

Impairment of axonal transport is an early pathologic event that precedes neurotoxicity in Alzheimer’s disease (AD). Soluble amyloid-β oligomers (AβOs), a causative agent of AD, activate intracellular signaling cascades that trigger phosphorylation of many target proteins, including tau, resulting in microtubule destabilization and transport impairment. Here, we investigated how KIF1A, a kinesin-3 family motor protein required for the transport of neurotrophic factors, is impaired in mouse hippocampal neurons treated with AβOs. By live cell imaging, we observed that AβOs inhibit transport of KIF1A-GFP similarly in wild-type and tau knock-out neurons, indicating that tau is not required for this effect. Pharmacological inhibition of glycogen synthase kinase 3β (GSK3β), a kinase overactivated in AD, prevented the transport defects. By mass spectrometry on KIF1A immunoprecipitated from transgenic AD mouse brain, we detected phosphorylation at S402, which conforms to a highly conserved GSK3β consensus site. We confirmed that this site is phosphorylated by GSK3β in vitro . Finally, we tested whether a phosphomimic of S402 could modulate KIF1A motility in control and AβO-treated mouse neurons and in a Golgi dispersion assay devoid of endogenous KIF1A. In both systems, transport driven by mutant motors was similar to that of WT motors. In conclusion, GSK3β impairs KIF1A transport but does not regulate motor motility at S402. Further studies are required to determine the specific phosphorylation sites on KIF1A that regulate its cargo binding and/or motility in physiological and disease states.

Amyloid-β Impairs Dendritic Trafficking of Golgi-Like Organelles in the Early Phase Preceding Neurite Atrophy: Rescue by Mirtazapine

“…In particular, under basal conditions, pGOLTtransfected neurons were characterized by an equal fraction of static, retrograde, and anterograde pGOLT vesicles, distributed along the entire dendritic tree. Short incubation with Aβ oligomers had a strong effect on vesicle trafficking, supporting the known effects of Aβ on molecular motors (Vicario-Orri et al, 2015;Gan and Silverman, 2016;Gan et al, 2020). In fact, we observed a significant reduction in the number of pGOLT vesicles as well as significant impairment in their mobility in both directions with respect to the control in all compartments analyzed.…”

“…Multiple mechanisms are involved in causing Aβ-induced neurodegeneration ( Resende et al, 2007 ). Among others, Aβ oligomers affect the structure and function of molecular motors required for neurite elongation, trafficking, and sorting of vesicles essential for synaptic function ( Brady and Morfini, 2017 ; Gan et al, 2020 ). In particular, Aβ induces Tau hyperphosphorylation and disengagement from microtubules affecting cargo transport, inducing deficits of neuronal protein transport, further leading to disruption of neuronal polarity ( Ballatore et al, 2007 ).…”

Phosphoregulation of Kinesins Involved in Long-Range Intracellular Transport

“…Complex intramolecular interactions involving the motor domain, neck-coil, the coiled-coil stalk and the FHA domain inactivate the Kinesin-3-family motor (Al-Bassam et al, 2003;Lee et al, 2004;Ren et al, 2018;Siddiqui et al, 2019). A recent study further showed that the Aβ-induced activation of GSK3β could attenuate Kif1A transport in neurites of the mouse hippocampal neurons (Gan et al, 2020). Although GSK3β phosphorylated S402 of rat Kif1A in vitro, it did not appear to alter the motility of an autoinhibition-deficient KIF1A, suggesting that phosphorylation of additional components may be involved in this process.…”

Spatially Resolved Transcriptomics Reveals Gene Signatures Underlying the Vulnerability of Human Middle Temporal Gyrus in Alzheimer's Disease

“…Interestingly, APLNR and SLC14A1 have also been found to be upregulated in AD [43][44][45][46] . The function of KIF1A has been shown to be impaired in the presence of Aβ oligomers 47 . While the repression of TAGLN3 has been recently reported to be attributed to APOE4 driven in ammation 48 and MTRNR2L6 peptides have been identi ed as neuroprotective species against Aβ toxicity in neurons and other cell types 49,50 .…”