Fig 2: SGTA interacted with glial cytoplasmic inclusions (GCIs) in multiple system atrophy (MSA). a Immunohistochemistry of postmortem tissue with anti-SGTA antibody in the substantia nigra of PD patients, in the medulla of MSA patients, in the spinal cord of ALS patients, and in the pontine nucleus of control patients. Control patients: scale bar = 20 μm, others: scale bar = 50 μm. Note that intense staining observed in the substantia nigra of PD patients represents the melanin pigments. Arrow heads indicate SGTA staining of GCIs in oligodendrocytes. b Double fluorescence immunohistochemistry labeling with anti-phosphorylated α-synuclein antibody (green) and anti-SGTA antibody (red) in the medulla of a patient with MSA. Scale bar = 50 μm

Fig 3: SGTA colocalized with neuronal intranuclear inclusions (NIIs) in postmortem brain sections of polyQ diseases. a Upper panels show immunohistochemistry of frozen brain sections of wild type (left) and R6/2 (right) mice using anti-SGTA antibody. Scale bars = 10 μm. Lower panels show double immunostaining images of the CA1 region in the hippocampus of the R6/2 mouse (left: ubiquitin, middle: SGTA, right: merged). Scale bars = 20 μm. b Immunohistochemistry with anti-SGTA antibody in the pontine nucleus of postmortem tissue from patients with polyQ diseases (spinocerebellar ataxias [SCA1, SCA2, SCA3] and dentatorubral–pallidoluysian atrophy [DRPLA]). NIIs indicated by arrow. Scale bar = 20 μm. c Double immunohistochemical labeling with the anti-polyQ antibody (green) and anti-SGTA antibody (red) in the pontine nucleus of postmortem tissue from a patient with SCA1. The nuclei were stained with DAPI. Scale bar = 20 μm

Fig 4: SGTA colocalized with polyQ aggregates in HD model cells. a Immunocytochemistry of Huntington disease (HD) model cells, HD150Q cells or HD 150QNLS cells. PolyQ aggregate formation was induced in these cells. Endogenous small glutamine-rich tetratricopeptide repeat (TPR)-containing protein alpha (SGTA) was labeled with anti-SGTA antibody (secondary antibody: Alexa Fluor 546). The nuclei were stained with 4′,6-diamidino-2-phenylindole (DAPI). Scale bar = 20 μm. b Cell lysates of Neuro2a wild type (WT), HD16Q, and HD150Q cells were fractionated into soluble and insoluble fractions. Immunoblotting with anti-SGTA, anti-LaminB and anti-1C2 antibodies was performed