Dynamic physiological roles of calcium binding proteins in the brain.

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Three Ca^<2+>-binding proteins in brain, calcineurin, phosphodiesterase and lipocortins, were studied and following results were obtained.l. calcineurin (CaN)・Monoclonal antibodies against alpha and beta were produced.・Immunohistochemical study elucidated the distinct distribution of both subunits in brain.・A novel beta subunit (beta_1) from rat testis was cloned and amino acid sequence was determined. Six additive hydrophilic amino acids were located in the carboxyl terminal of the molecule as compared to the bovine type beta subunit.・Two isoforms of alpha subunit of bovine brain CaN were demonstrated by Western blot analysis using the monoclonal antibody.・A part of CaN could translocate from cytosoi to membrane in a Ca^<2+> dependent manner.2. phosphodiesterase (PDE)・A monclonal antibody was raised.・Two isozymes, PDE_1, (Mr=63, 000) and PDE_2 (Mr=60, 000), were identified.・PDE_1 and PDE_2 were phosphorylated by protein kinase C and cyclic-AMP dependent protein kinase, respectively.・PDE_1 and PDE_2 showed a distinct distribution in rat brain.3. lipocortins (LP)・Monoclonal antibodies against LP-I (Mr=35, 000) and LP-II (Mr=36, 000) were produced.・Both LP-I and LP-II inhibited phospholipase A_2 activity, and phosphorylated forms of both proteins by protein kinase C showed a reduced inhibitory activity on phospholipase A_2.・LP-I and LP-11 showed a developmental change in amount ; higher quantity in newborn rat brain and lower in adult brain.・Specific distribution in astrocytes (not in neurons) was confirmed.