Amyloid beta protein (25-35) phosphorylates MARCKS through tyrosine kinase-activated protein kinase C signaling pathway in microglia.
Myristoylated alanine-rich C kinase substrate (MARCKS) is a widely distributed specific protein kinase C (PKC) substrate and has been implicated in membrane trafficking, cell motility, secretion, cell cycle, and transformation. We found that amyloid beta protein (A beta) (25-35) and A beta (1-40) phosphorylate MARCKS in primary cultured rat microglia. Treatment of microglia with A beta (25-35) at 10 nM or 12-O-tetradecanoylphorbol 13-acetate (1.6 nM) led to phosphorylation of MARCKS, an event inhibited by PKC inhibitors, staurosporine, calphostin C, and chelerythrine. The A beta (25-35)-induced phosphorylation of MARCKS was inhibited by pretreatment with the tyrosine kinase inhibitors genistein and herbimycin A, but not with pertussis toxin. PKC isoforms alpha, delta, and epsilon were identified in microglia by immunocytochemistry and western blots using isoform-specific antibodies. PKC-delta was tyrosine-phosphorylated by the treatment of microglia for 10 min with A beta (25-35) at 10 nM. Other PKC isoforms alpha and epsilon were tyrosine-phosphorylated by A beta (25-35), but only to a small extent. We propose that a tyrosine kinase-activated PKC pathway is involved in the A beta (25-35)-induced phosphorylation of MARCKS in rat microglia.
Hyogo Institute for Aging Brain and Cognitive Disorders, Himeji, Japan.
M
M
Nakai
K
K
Hojo
K
K
Yagi
N
N
Saito
T
T
Taniguchi
A
A
Terashima
T
T
Kawamata
T
T
Hashimoto
K
K
Maeda
M
M
Gschwendt
H
H
Yamamoto
E
E
Miyamoto
C
C
Tanaka
D016229:Amyloid beta-Peptides / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D015151:Immunoblotting; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes / Q000378:metabolism; D008565:Membrane Proteins; D017628:Microglia / Q000187:drug effects / Q000201:enzymology*; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010446:Peptide Fragments / Q000494:pharmacology*; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D011233:Precipitin Tests; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects*
D016229:Amyloid beta-Peptides; D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes; C000619712:Marcks protein, rat; D008565:Membrane Proteins; D010446:Peptide Fragments; D010761:Phosphorus Radioisotopes; D011506:Proteins; C113041:amyloid beta-protein (35-25); D000076250:Myristoylated Alanine-Rich C Kinase Substrate; C497260:Prkcd protein, rat; C497257:Prkce protein, rat; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon