As exposure stimulates the accumulation of α-synuclein (SYN) into intracellular inclusions and it’s colocalization with the autophagy marker light chain 3 (LC3). All trans retinoic acid differentiated SH-SY5Y cells were exposed to 25 ppb As for 72 h, and immunocytochemical analysis performed on (A) control, (B) As-exposed cells, (C) Colocalization of SYN (red) and LC3 (green) in As-exposed cells. Cells were stained for SYN (red), nuclear stain (blue), or LC3 (green), Scale bar = 10 μm.