Can't speak to the interaction with the Americans, but when it comes to Israel there is an agreement between Russia and Israel on spheres of influence in Syria; Israel doesn't interfere with Russian strikes on rebels in the north and east (which Israel doesn't care about), and Russia doesn't interfere with Israeli strikes on Hezbollah and Iranian forces in the south and west (which Russia doesn't care about).

The two countries just don't have a clear enough conflict of interest to want to get into a fight about it.