Cell type-specific upregulation of myristoylated alanine-rich C kinase substrate and protein kinase C-alpha, -beta I, -beta II, and -delta in microglia following kainic acid-induced seizures.
Myristoylated alanine-rich C kinase substrate (MARCKS) is a widely distributed protein kinase C (PKC) substrate and has been implicated in actin cytoskeletal rearrangement in response to extracellular stimuli. Although MARCKS was extensively examined in various cell culture systems, the physiological function of MARCKS in the central nervous system has not been clearly understood. We investigated alterations of cellular distribution and phosphorylation of MARCKS in the hippocampus following kainic acid (KA)-induced seizures. KA (25 mg/kg, i.p.) was administered to eight to nine week-old C57BL/6 mice. Behavioral seizure activity was observed for 2 h after the onset of seizures and was terminated with diazepam (8 mg/kg, i.p.). The animals were sacrificed and analyzed at various points in time after the initiation of seizure activity. Using double-labeling immunofluorescence analysis, we demonstrated that the expression and phosphorylation of MARCKS was dramatically upregulated specifically in microglial cells after KA-induced seizures, but not in other types of glial cells. PKC alpha, beta I, beta II and delta, from various PKC isoforms examined, also were markedly upregulated, specifically in microglial cells. Moreover, immunoreactivities of phosphorylated MARCKS were co-localized in the activated microglia with those of the above isoforms of PKC. Taken together, our in vivo data suggest that MARCKS is closely linked to microglial activation processes, which are important in pathological conditions, such as neuroinflammation and neurodegeneration.
Eun
Su Yong
SY
Department of Physiology, Cheju National University College of Medicine, Jeju 690-756, Korea.
Kim
Eun Hae
EH
Kang
Kee Seok
KS
Kim
Hwa Jung
HJ
Jo
Sangmee Ahn
SA
Kim
Soon Jong
SJ
Jo
Su Hyun
SH
Kim
Sang Jeong
SJ
Blackshear
Perry J
PJ
Kim
Jun
J
D000818:Animals; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000032:analysis* / Q000378:metabolism; D007527:Isoenzymes / Q000032:analysis; D007608:Kainic Acid / Q000633:toxicity*; D008565:Membrane Proteins / Q000032:analysis* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018613:Microscopy, Confocal; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010766:Phosphorylation / Q000187:drug effects; D014176:Protein Biosynthesis / Q000187:drug effects; D011493:Protein Kinase C / Q000032:analysis*; D051571:Protein Kinase C-alpha / Q000032:analysis; D051745:Protein Kinase C-delta / Q000032:analysis; D012640:Seizures / Q000139:chemically induced / Q000378:metabolism*; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects
D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes; C000619711:Marcks protein, mouse; D008565:Membrane Proteins; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D007608:Kainic Acid