We all know that Milky Way exhibits Galaxy Rotation Curve which makes it rotate very differently that Newtonian mechanics would expect. But Milky Way is a pretty large galaxy, and the one we only see inside, so maybe it's not that good of an research object.
What are the smallest galaxies or star clusters whose rotation is clearly non-Newtonian? Are dwarf galaxies' rotation curves affected? Are globular clusters inside galaxies such as ours affected, or is their movement decisively Newtonian?