Protein kinase A regulatory subunit distribution in medulloblastoma.

Background: Previous studies showed a differential distribution of the four regulatory subunits of cAMPdependent protein kinases inside the brain, that changed in rodent gliomas: therefore, the distribution of these proteins inside the brain can give information on the functional state of the cells. Our goal was to examine human brain tumors to provide evidence for a differential distribution of protein kinase A in different tumors. Methods: The distribution of detergent insoluble regulatory (R1 and R2) and catalytic subunits of cAMP dependent kinases was examined in pediatric brain tumors by immunohistochemistry and fluorescent cAMP analogues binding. Results: R2 is organized in large single dots in medulloblastomas, while it has a different appearance in other tumors. Fluorescent cAMP labelling was observed only in medulloblastoma. Conclusions: A different distribution of cAMP dependent protein kinases has been observed in medulloblastoma.