Fig. 2

ER aggregation of C-terminally truncated forms of provasopressin. a Schematic representation of C-terminally truncated provasopressin mutants C61myc (corresponding to 1-72myc), 1-60myc, and 1-50myc. The myc epitope is shown in purple. b These constructs were expressed in HN10 cells and visualized by immunofluorescence microscopy. Cells expressing C61myc were costained for the ER chaperone calreticulin. Nuclei were stained with DAPI (blue). Bar: 10 μm. c The fraction of expressing cells with ER aggregates was quantified and plotted (mean and individual values of four independent transfections, analyzing ~200 expressing cells per transfection). d Immunoblot analysis of untransfected cells (−) and transfected cells expressing C61myc after reducing SDS-gel electrophoresis. Molecular weight standards are indicated in kilodaltons. e Electron micrographs of C61myc aggregates forming a fibrillar network decorated with 10-nm gold. The surrounding rough ER membrane is visible in the left micrograph. Bars: 200 nm. Below, a section is shown enlarged with and without fibrillar lines highlighted for clarity