Final answer:
The false statement about mannose 6-phosphate and lysosomal protein sorting is that lysosomal enzymes are synthesized on the lysosome; instead, they are synthesized in the RER, then modified, packaged with a M6P signal in the Golgi, and distributed to lysosomes.
Explanation:a
The statement that is FALSE regarding mannose 6-phosphate (M6P) and the sorting and targeting of lysosomal proteins is that lysosomal enzymes are synthesized on the lysosome. In fact, lysosomal enzymes are synthesized in the rough endoplasmic reticulum (RER), modified in the Golgi apparatus, and then packaged into vesicles.
The correct sequence involves synthesis of proteins in the RER, modification in the Golgi apparatus, packaging into vesicles that contain M6P as a signal for lysosomal targeting, and distribution of these proteins to their final destinations including the lysosomes. A key step in this process is the tagging of these proteins with the mannose 6-phosphate in the Golgi, which serves as a signal for the proteins to be delivered to the lysosomes. This modification allows for the correct sorting of the enzymes so that they can function properly in protein digestion and turnover.