ATP13A2 knockdown (KD) results in upregulation of αsyn multimers in SH-SY5Y cells. (a) Visualization of α-synuclein (αsyn) multimers by Western blot after cross-linking in ATP13A2 KD, control fLuc, ATP13A2 wildtype (WT), and ATP13A2 D508N (DN) cells. (b) Quantification of disuccinimidyl glutarate (DSG) cross-linked αsyn-60 + αsyn-80 + αsyn-100 + HMW (high molecular weight) αsyn relative to dithiobis succinimidyl propionate (DSP) αsyn-14 monomer in the ATP13A2 KD, ATP13A2 WT, and ATP13A2 DN cells relative to the ratio in the control cells (n = 4). Statistical analysis was performed using a one-way ANOVA test with Bonferroni. The error bars represent the standard error of the mean (SEM). * p < 0.05, ns, not significant. αsyn-60 = ~60 kDa αsyn, αsyn-80 = ~80 kDa αsyn, αsyn-100 = ~100 kDa αsyn.