Final answer:
A sorting signal that might target a protein for secretion is a short tail of amino acids known as a signal sequence, which directs the protein to its specific cellular compartment. Once the protein reaches its destination, the signal sequence is usually removed.
Step-by-step explanation:
A sorting signal that might target a protein for secretion is a short tail of amino acids known as a signal sequence. This signal sequence directs the protein to its specific cellular compartment, acting like a 'train ticket' to its ultimate destination. Once the protein reaches its destination, the signal sequence is usually clipped off. Examples of cellular compartments include the mitochondria or chloroplasts in plants.