Where do proteins synthesized in the cytosol typically go through the secretory pathway?

Proteins synthesized in the cytosol that follow the secretory pathway are directed towards various destinations, including the cell membrane, lysosomes, or the extracellular space. These proteins are initially synthesized in the ribosomes located in the cytosol, and once they have specific signal sequences, they will enter the secretory pathway by being translocated into the endoplasmic reticulum (ER). From the ER, they are processed and then transported to the Golgi apparatus for further modification and sorting. After this processing, they can be directed to the cell membrane, where they may function as receptors or transporters, or to lysosomes for degradation of cellular waste, or they could be secreted into the extracellular space, where they may act as signaling molecules or components of the extracellular matrix.

The other options provide locations or processes that are less relevant to the typical trajectory of cytosolic proteins in the secretory pathway. The nucleus and mitochondria, for example, are more related to proteins that have specific targeting signals for those organelles, rather than for proteins meant to enter the secretory pathway. Similarly, while the Golgi apparatus is part of the secretory pathway, ribosomes are not a destination but rather the site of initial protein synthesis. Vac