Influence of Chr21 protein over-expression on cellular physiology. Over-expressed claudin-14 was retained in the retracted endoplasmic reticulum (a), which resulted in loss of cell-membrane protrusions (b). Claudin-17 localized in the plasma membrane and its expression did not influence cell morphology. A distinct change in nuclear shape (c) was observed in cells expressing claudin-14 but not in those expressing claudin-17. The scale bar represents 10 μm.