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Figure. Autoantigens cluster in unique subcellular structures generated during apoptosis. A normal and an apoptotic cell are shown in this Fig. (left and right, respectively). Sjögren’s syndrome autoantigens are not restricted to any specific subcellular compartment in normal cells (e.g., Ro52 is cytoplasmic, the golgins are located in the Golgi apparatus, and Ku/DNA-PK is nuclear). Single crescent shapes depict the golgi apparatus, stacked crescents represent ER, and dots and rectangles represent endocytic vesicles and mitochondria, respectively. In cells dying by apoptosis induced by numerous different apoptotic stimuli, the antigens targeted in SS become clustered and concentrated within small surface blebs (derived from the ER and cytoplasm) and apoptotic bodies (derived from the fragmented nucleus). The precise bleb location of Golgi fragments in apoptotic cells is not yet confirmed.
