The Localization of Alpha-synuclein in the Endocytic Pathway.

Mohammad A A Fakhree, Irene B M Konings, Jeroen Kole, Alessandra Cambi, Christian Blum, Mireille M A E Claessens

Neuroscience 2021 Mar 01

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Alpha-synuclein (αS) is an intrinsically disordered protein (IDP) that is abundantly present in the brain and is associated with Parkinson's disease (PD). In spite of its abundance and its contribution to PD pathogenesis, the exact cellular function of αS remains largely unknown. The ability of αS to remodel phospholipid model membranes combined with biochemical and cellular studies suggests that αS is involved in endocytosis. To unravel with which route(s) and stage(s) of the endocytic pathway αS is associated, we quantified the colocalization between αS and endocytic marker proteins in differentiated SH-SY5Y neuronal cells, using an object based colocalization analysis. Comparison with randomized data allowed us to discriminate between structural and coincidental colocalizations. A large fraction of the αS positive vesicles colocalizes with caveolin positive vesicles, a smaller fraction colocalizes with EEA1 and Rab7. We find no structural colocalization between αS and clathrin and Rab11 positive vesicles. We conclude that in a physiological context, αS is structurally associated with caveolin dependent membrane vesiculation and is found further along the endocytic pathway, in decreasing amounts, on early and late endosomes. Our results not only shed new light on the function of αS, they also provide a possible link between αS function and vesicle trafficking malfunction in PD. Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Citation

Mohammad A A Fakhree, Irene B M Konings, Jeroen Kole, Alessandra Cambi, Christian Blum, Mireille M A E Claessens. The Localization of Alpha-synuclein in the Endocytic Pathway. Neuroscience. 2021 Mar 01;457:186-195