Preparation of microsomes to study Ca²⁺ channels

Native cerebellar microsomes are used to study the properties of native cerebellar inositol(1,4,5)- trisphosphate receptor 1 (InsP₃R1) and ryanodine receptor 1 (RyanR1) Ca²⁺ release channels. Additionally, microsomes prepared from Sf9 cells infected with InsP3R- or RyanR-expressing recombinant baculoviruses can be used to compare properties of different InsP₃R and RyanR isoforms and to perform structure-function studies of both types of receptors. This protocol describes how to prepare ER microsomes from native cerebellar tissue or Sf9 cells infected with InsP₃R- or RyanRexpressing recombinant baculoviruses for planar lipid bilayer (also called black lipid membranes or BLM) experiments. Prepared material is aliquoted and can be stored at -80°C freezer for many months before BLM experiments.