FIG. 13.

Schematic diagram showing changes in p31-deficient cells. In p31-deficient cells, a two-stage change in ER structure was observed; vesiculation and subsequent enlargement (fusion) of vesiculated membranes. Thus, the tubular structure of the ER was completely disorganized. This suggests that p31 is involved in the maintenance of ER tubules and prevention of random fusion of ER structures. The disorganized ER structure causes inefficient ER-to-Golgi complex protein transport, which results in ER stress-induced apoptosis. The ER and Golgi complex are blue and green, respectively.