[Alzheimer-like protein phosphatase deficiency leads to abnormal phosphorylation and accumulation of neurofilaments].
OBJECTIVE
To explore the effect of Alzheimer-like protein phosphatase deficiency on neurofilament phosphorylation.


METHODS
Cell culture, light microscopy, immunocytochemistry and biochemistry techniques were used to make a phosphatase deficient cell model, to detect cell morphology, neurofilament phosphorylation and distribution, cell viability and activity.


RESULTS
Non-phosphorylated neurofilament recognized by SMI32 was detected both in cell body and cell processes, it was extremely enriched in cell bodies; Phosphorylated neurofilament bound to SMI34 was mainly determined in cell processes and cell surface. After treatment with okadaic acid (OA), non-phosphorylation-dependent antibodies SMI32 staining was significantly decreased in the cell body, whereas phosphorylated neurofilament reacted with SMI34 was strikingly increased in immunocytochemistry and Western blot, and prominently accumulated to the same cell location. Accompanied with hyper-phosphorylation and accumulation of neurofilament, dose dependent cell toxicity was observed by okadaic acid treatment.


CONCLUSIONS
Deficiency in protein phosphatase induces in neuroblastoma cell line, neurofilament phosphorylation and accumulation, which is involved in Alzheimer neurofibrillary degeneration.
Li
X T
XT
Department of Pathophysiology, Tongji Medical College, Huazhong Science and Technology University, Wuhan 430030, China.
Wang
Q
Q
Wei
Z L
ZL
Yuan
Y H
YH
Wang
J Z
JZ
D000544:Alzheimer Disease / Q000201:enzymology / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D016900:Neurofilament Proteins / Q000378:metabolism*; D019319:Okadaic Acid / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000172:deficiency*; D010766:Phosphorylation; D014407:Tumor Cells, Cultured
D004791:Enzyme Inhibitors; D016900:Neurofilament Proteins; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases