Characterization of the cell fraction used for channel incorporation.

<p>Membranes were probed with organelle specific antibodies. A) Plasma membrane marker: Actin (C-11), 45 kDa; Golgi marker: 58 K Goli protein; endoplasmic reticulum marker: Calnexin, 90 kDa, and in B) Mitochondrial membrane marker: Cox1 (1D6), 39 kDa. Although mitochondrial membranes were present in the homogenate (step 1) these membranes were removed through the purification procedure we used to obtain RER membranes (step 4). Steps 1 and 4 are described in the “methods and materials” section.