An excess of any macronutrient will lead to fat gain.
However, Protein takes more calories than the other macro.s to digest, and I believe the process in which it is converted to fat is very costly, metabolically.
Therefore, fat storage from too much protein is not so common, or a concern.
The excess is whizzed away down the loo.
The late Dan Duchaine, said he has very rarely seen anyone get fat from eating too much protein.
However, too much carbs and or fats (and even at the wrong times) can lead to fat gain alot easier, and much more of a concern.