PHOSPHORYLATION AND SPATIOTEMPORAL DISTRIBUTION OF KW8 (NDRF NEUROD2), A NEUROD FAMILY BASIC HELIX-LOOP-HELIX PROTEIN/

KW8, a NeuroD family basic helix-loop-helix protein, was initially clo ned during the course of screening for the genes related to long term potentiation in rat hippocampal slice. Its homologue NDRF/NeuroD was a lso reported. In this report its phosphorylation and spatiotemporal di stribution was studied. KW8 was expressed not only during embryonic an d neonatal periods but also in adults. In adult, KW8 was expressed onl y in brain tissues, such as the cerebral cortex, hippocampus and cereb ellum. Immunohistological studies revealed that KW8 was localized in t he nuclei of neurons. On immunoblotting of rat brain tissue, COS-1 cel ls and Neuro2A cells overexpressing KW8, this protein was detected as several diffuse bands. Alkaline phosphatase treatment reduced the mole cular weights of these bands. Metabolic labeling with (32)Pi in COS-1 cells confirmed that the KW8 protein was phosphorylated in vivo. Some of the physiological functions of KW8 might be regulated by this phosp horylation. In yeast, the GAL4 fusion protein containing the C-termina l region of KW8 activated transcription of the reporter gene, suggesti ng that KW8 had transcriptional activity. (C) 1998 Elsevier Science B. V. All rights reserved.