Role of Membrane Cholesterol Levels in the Lateral Diffusion and Function of the Novel Slow Channel Congenital Myasthenia Syndrome αC418W AChR Mutant

Abstract

with >70% of the labeling in the b2 subunit. [ 3 H]chlorpromazine subunit labeling was inhibited (~40%) by the non-competitive antagonist PCP (Fig 1). When HPLC-purified EndoLys-C digests of [ 3 H]chlorpromazine-labeled b2 subunit was sequenced, a PCP-inhibitable 3 H release at cycle 6 was evident, consistent with labeling of b2Ser246 (M2-6), the position photolabeled by [ 3 H]chlorpromazine in the Torpedo nAChR ion channel. Sequence analyses of HPLC-purified EndoLys-C/V8 protease digests of a4 and b2 subunits photolabeled by [ 3 H]TDBzl-etomidate indicated the presence of multiple sites of 3 H incorporation. Studies are in progress to identify amino acids labeled by [ 3 H]TDBzl-Etomidate and [ 3 H]chlorpromazine.