<prompt> In Myasthenia gravis, antibodies are present againstMuscarinic receptor proteinsNicotinic receptor proteinsProtein actinProtein myosin  <response>: Robbins basic pathology 9th edition page no 800,headingMyasthenia gravis Myasthenia gravis is caused by autoantibodies that block the function of postsynaptic acetyl choline nicotinic receptors at motor end plates, which results in the degradation and depletion of the receptors. ref img : 