|MadSci Network: Cell Biology|
The ER and the nuclear membrane are contiguous. The membrane material of the cell is constantly recycling from the outer nuclear membrane, through the ER to the golgi apparatus and from there to to the plasma membrane during exocytosis. This process of moving membranous vesicles from the nuclear membrane to the plasma membrane is balanced by the opposite process of endocytosis. (Alberts et al, Mol. Biology of the Cell, 3rd Edition, New York: Garland Press, 1994). Please remember that the nuclear membrane is disrupted during mitosis, but that otherwise it is intact. I hope that this helps! If this did not completely answer your question, please e-mail me back and I can go into more detail. Ingrid Dodge :)
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