What happens to proteins that do not have a retention signal?

Proteins that do not have a retention signal are typically allowed to leave the organelle where they were synthesized, such as the endoplasmic reticulum (ER). Each organelle, like the ER, Golgi apparatus, or lysosome, often has specific retention signals that help maintain the proteins where they are functionally required. If a protein lacks such a signal, it is not anchored to the organelle and thus can be transported out, possibly to be secreted or sent to another cellular location where it may be needed. This process ensures that proteins are efficiently utilized in various parts of the cell, allowing for necessary functions to occur throughout the cellular environment.

In contrast, the other options suggest immediate degradation, accumulation in the ER, or misfolding, which are processes that specifically concern proteins that either fail to fold properly or do not reach their designated location within the cell. However, without a retention signal, the main fate is for these proteins to exit the organelle rather than encounter pathways leading to degradation or misfolding.