Cytoplasmic Location of α1A Voltage-Gated Calcium Channel C-Terminal Fragment (Cav2.1-CTF) Aggregate Is Sufficient to Cause Cell Death
Figure 5
CREB and Cav2.1 aggregates co-localize in SCA6 human Purkinje cells.
(A) In a control brain affected with Parkinson's disease, the immunoreactivity against CREB is present but weak and homogeneous in the neuronal cytoplasm of two Purkinje cells. (B) In SCA6 human Purkinje cells, focally accentuated immunoreactive structures (arrows) are seen in the cytoplasm. (C) In ten control brains, a vast majority of Purkinje cells showed weak and diffuse immunoreactivity for the anti-CREB antibody as demonstrated in the Figure 5 A. In contrast, aggregate-like CREB-immunoreactive structures were seen in the Purkinje cells from three SCA6 cerebella. Please refer to the Materials and Methods for the detailed description on the criteria of CREB-immunoreactivities. (D) On double immunofluorescence analysis using a rabbit polyclonal CREB antibody and 1C2, a mouse monoclonal antibody against expanded polyQ tracts, microscopic Cav2.1 aggregates in the cytoplasm of the SCA6 Purkinje cells indeed co-localized with CREB (arrows). (For A&B: scale bars: 50 µm; for D&E: scale bar: 10 µm). (E) In three SCA6 cerebella, approximately 50% of Purkinje cells containing 1C2-positive polyQ aggregates in the cytoplasm showed co-localization of the polyQ aggregates and CREB. In contrast, the Purkinje cells in control cerebella did not show 1C2-positive aggregates resulting in no co-localizations.