On remaining cytoplasmic.

The published literature contains a number of examples of normally non-cytoplasmic proteins whose transport out of the cytoplasm is not completely abolished by drastic alterations to their routing signals (signal sequences, etc). Furthermore, there are numerous examples of cytoplasmic proteins that can be routed to and across plasma or organelle membranes by fusing them to routing signals. These 2 sets of observations lead to a re-evaluation of the reliability and accuracy of protein routing and to consideration of the consequences of the errors which might occur.