mTOR pathway stands for mammalian target of rapamycin. It's a pathway that creates muscles and or helps in the recovery process. It is stimulated by protein, in particular the amino acid Leucine. 3 grams of Leucine are needed which is around the equivalent of 30 grams of protein.
If you have less protein then is needed for the mTOR pathway to be stimulated the body treats the protein just like it would carbs/fats, as energy.
Each meal then should have a target of 20-30 grams of protein. The size of your fist or a scoop or two of protein powder. The discrepancy in numbers varies from study to study.
The mTOR pathway is a potentially critical pathway when it comes to muscle building. There is some disagreement in meal frequency, but going by the numbers it would take 3-6 meals to get the required protein to meet your anabolic goals. Most research will state 1 gram of protein per pound of lean mass or target bodyweight. So if your goal is to weigh 180lbs. 180 grams of protein is needed. Say 30 grams per meal and that is 6 meals. 60 grams of protein and 3 meals is needed. I would doubt you would eat more then 60 per meal comfortably.
If building muscle or preservation of muscle is important to you, the mTOR pathway must be considered. 30 grams of protein per meal will be on the safe side as you either build muscle or retain muscle.
Remember, homeostasis is a never ending process, you are never just the same. Better or worse. Building or losing. Retain your muscle as you age. Better yet, build some more.