Fig 2: IHC of serial mouse cerebellar sections.(A) Immunohistochemical staining with 4E10 IgG in mouse cerebellum sections reveals perinuclear, nodular immunoreactivity in Purkinje neurons; inset shows a magnified view. (B) Human IgG Isotype control staining of mouse cerebellum is shown. (C) Staining for IP3R1 with an anti-IP3R1 IgG shows a perinuclear, nodular and diffuse cytoplasmic staining pattern in Purkinje neurons, mirroring that seen in (A); inset shows a magnified view. (D) Rabbit IgG isotype control staining of mouse cerebellum is shown.

Fig 3: PhIP-Seq analyses of 4E10 and b12.PhIP-Seq results are plotted as -Log10 P values, one replicate on the abscissa, the other on the ordinate; note the discontinuity in axis scales. The top five scoring 4E10 peptides are highlighted with arrows; the three peptides derived from IP3R isoform sequences are highlighted with green arrows, with the consensus core sequence shown as a MEME logo [72], [111] in the inset. The orange arrow corresponds to a peptide derived from cytoplasmic dynein 1 and the blue arrow to a peptide derived from complement receptor type 1. The gray arc corresponds to the -Log10 P values observed for the highest-scoring b12 peptide, so defines a threshold for potential autoreactive binding events. Proximity to the diagonal indicates good replicate concordance; peptides with highly discordant replicate values, falling along the axes, outside the bounding dashed red lines were discarded from the analysis.