Nanomolar amyloid beta protein activates a specific PKC isoform mediating phosphorylation of MARCKS in Neuro2A cells.
Myristoylated alanine-rich C kinase substrate (MARCKS), a protein associated with cell growth, neurosecretion and macrophage activation, is activated by protein kinase C (PKC) phosphorylation. We reported that amyloid beta protein (Abeta) activated MARCKS through a tyrosine kinase and PKC-delta in rat cultured microglia. Here we report that Abeta signaling pathway through a specific PKC isoform is involved in the phosphorylation of MARCKS in Neuro2A cells. Selective PKC inhibitors but not tyrosine kinase inhibitors significantly inhibited the phosphorylation of MARCKS induced by Abeta. Abeta selectively activated PKC-alpha among the four PKC isoforms localized in Neuro2A cells. PKC-alpha activated by Abeta directly phosphorylated a recombinant MARCKS in vitro, Translocation of PKC-alpha from the cytoplasm to the membrane and accumulation of phospho-MARCKS in the cytoplasm were induced by Abeta. These results suggest involvement of a phosphoinositide signaling system through PKC-alpha in the phosphorylation of MARCKS in neurons, an event which may be associated with mechanisms underlying neurotrophic and neurotoxic effects of Abeta.
Tanimukai
Satoshi
S
Hyogo Institute for Aging Brain and Cognitive Disorders, 520 Saisho-ko, Himeji 670-0981, Japan.
Hasegawa
Hiroshi
H
Nakai
Masamichi
M
Yagi
Keiko
K
Hirai
Midori
M
Saito
Naoaki
N
Taniguchi
Taizo
T
Terashima
Akira
A
Yasuda
Minoru
M
Kawamata
Toshio
T
Tanaka
Chikako
C
D016229:Amyloid beta-Peptides / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D002135:Calcium-Binding Proteins; D005959:Glucosidases; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes / Q000378:metabolism; D008565:Membrane Proteins; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014407:Tumor Cells, Cultured
D016229:Amyloid beta-Peptides; D002135:Calcium-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes; C000619710:MARCKS protein, human; C000619712:Marcks protein, rat; D008565:Membrane Proteins; D010750:Phosphoproteins; C512948:Prkcsh protein, rat; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; C496628:PRKCA protein, human; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D005959:Glucosidases; C070368:PRKCSH protein, human