J Erlichman

Regional localization of the regulatory subunit (RIIβ) of the type II cAMP-dependent protein kinase in human brain

The distribution of the regulatory (RII beta) subunits of type II cAMP-dependent protein kinase in cortical and subcortical areas was examined in human control and Alzheimers disease (AD) brains. Four monoclonal antibodies generated against bovine brain RII, which cross-reacted with human brain RII beta, detected RII-immunoreactivity in pyramidal neurons of the hippocampus and frontal, occipital, parietal and superior temporal cortices and in non-pyramidal neurons of the amygdala and putamen. RII beta immunoreactivity was localized to neuronal perikarya, proximal dendrites and cell processes. With the exception of rare processes in the ventroposterior lateral nucleus, RII-immunoreactivity was not seen in the thalamus. Other areas lacking RII-immunoreactivity included the midbrain, caudate nucleus and globus pallidus. RII-immunoreactivity was not detected in endothelia or glia. Except for the neocortex, the distribution of RII beta immunoreactivity was the same in AD and non-demented control brains; however, cell bodies and their processes stained more intensely and uniformly in the neocortical regions of non-demented controls compared to AD. In the neocortex of AD, RII beta immunoreactivity was substantially decreased in the superior temporal and occipital cortices, but not in the frontal cortex. Our data suggest that RII subunits are regionally distributed in the human brain. RII-immunoreactivity was decreased in some regions of neocortex in AD, but it did not preferentially colocalize with neurofibrillary tangles (NFT), senile plaques, or neuropil threads.

Use of immunological approaches to identify a brain protein kinase isozyme

Publisher Summary This chapter describes the use of immunological approach to identify a brain protein kinase isozyme. Type II cAMP-dependent protein kinases (PKs) from many mammalian tissues appear to be very closely related based on their physicochemical and kinetic properties, subunit compositions, and mode of activation by cAMP. For example, homogeneous preparations of the prototypic heart and skeletal muscle type II PKs are virtually identical in size, shape, ion-exchange properties, and isoelectric point. The immunological techniques of indirect immunoprecipitation and competitive binding immunoassay can be combined with functional assays to address the question of whether there are subclasses of type II PKs.. Antibodies raised against bovine cerebral cortex R II have been employed as highly specific and sensitive probes for identifying and characterizing tissue-specific subclasses of type II PKs.