scholarly journals Feedback Regulation of Raf-1 and Mitogen-activated Protein Kinase (MAP) Kinase Kinases 1 and 2 by MAP Kinase Phosphatase-1 (MKP-1)

1998 ◽  
Vol 273 (3) ◽  
pp. 1788-1793 ◽  
Author(s):  
Paul S. Shapiro ◽  
Natalie G. Ahn
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Feedback Regulation ◽  
Mitogen Activated Protein Kinase ◽  
Map Kinase Phosphatase ◽  
Mitogen Activated Protein

scholarly journals Genetic Complementation Screen Identifies a Mitogen-activated Protein Kinase Phosphatase, MKP3, as a Regulator of Dopamine Transporter Trafficking

2008 ◽  
Vol 19 (7) ◽  
pp. 2818-2829 ◽  
Author(s):  
Ole Valente Mortensen ◽  
Mads Breum Larsen ◽  
Balakrishna M. Prasad ◽  
Susan G. Amara
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Dopamine Transporter ◽  
Map Kinases ◽  
Kinase Inhibitors ◽  
Mitogen Activated Protein Kinase ◽  
Genetic Complementation ◽  
Monoamine Transporters ◽  
Map Kinase Phosphatase ◽  
Mitogen Activated Protein

The antidepressant and cocaine sensitive plasma membrane monoamine transporters are the primary mechanism for clearance of their respective neurotransmitters and serve a pivotal role in limiting monoamine neurotransmission. To identify molecules in pathways that regulate dopamine transporter (DAT) internalization, we used a genetic complementation screen in Xenopus oocytes to identify a mitogen-activated protein (MAP) kinase phosphatase, MKP3/Pyst1/DUSP6, as a molecule that inhibits protein kinase C–induced (PKC) internalization of transporters, resulting in enhanced DAT activity. The involvement of MKP3 in DAT internalization was verified using both overexpression and shRNA knockdown strategies in mammalian cell models including a dopaminergic cell line. Although the isolation of MKP3 implies a role for MAP kinases in DAT internalization, MAP kinase inhibitors have no effect on internalization. Moreover, PKC-dependent down-regulation of DAT does not correlate with the phosphorylation state of several well-studied MAP kinases (ERK1/2, p38, and SAPK/JNK). We also show that MKP3 does not regulate PKC-induced ubiquitylation of DAT but acts at a more downstream step to stabilize DAT at the cell surface by blocking dynamin-dependent internalization and delaying the targeting of DAT for degradation. These results indicate that MKP3 can act to enhance DAT function and identifies MKP3 as a phosphatase involved in regulating dynamin-dependent endocytosis.

scholarly journals A Role for Mitogen-activated Protein Kinase in the Spindle Assembly Checkpoint in XTC Cells

1997 ◽  
Vol 137 (2) ◽  
pp. 433-443 ◽  
Author(s):  
Xiao Min Wang ◽  
Ye Zhai ◽  
James E. Ferrell
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Map Kinases ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Mitogen Activated Protein Kinase ◽  
Mitotic Progression ◽  
Map Kinase Phosphatase ◽  
Mitogen Activated Protein ◽  
Map Kinase Kinase

The spindle assembly checkpoint prevents cells whose spindles are defective or chromosomes are misaligned from initiating anaphase and leaving mitosis. Studies of Xenopus egg extracts have implicated the Erk2 mitogen-activated protein kinase (MAP kinase) in this checkpoint. Other studies have suggested that MAP kinases might be important for normal mitotic progression. Here we have investigated whether MAP kinase function is required for mitotic progression or the spindle assembly checkpoint in vivo in Xenopus tadpole cells (XTC). We determined that Erk1 and/or Erk2 are present in the mitotic spindle during prometaphase and metaphase, consistent with the idea that MAP kinase might regulate or monitor the status of the spindle. Next, we microinjected purified recombinant XCL100, a Xenopus MAP kinase phosphatase, into XTC cells in various stages of mitosis to interfere with MAP kinase activation. We found that mitotic progression was unaffected by the phosphatase. However, XCL100 rendered the cells unable to remain arrested in mitosis after treatment with nocodazole. Cells injected with phosphatase at prometaphase or metaphase exited mitosis in the presence of nocodazole—the chromosomes decondensed and the nuclear envelope re-formed—whereas cells injected with buffer or a catalytically inactive XCL100 mutant protein remained arrested in mitosis. Coinjection of constitutively active MAP kinase kinase-1, which opposes XCL100's effects on MAP kinase, antagonized the effects of XCL100. Since the only known targets of MAP kinase kinase-1 are Erk1 and Erk2, these findings argue that MAP kinase function is required for the spindle assembly checkpoint in XTC cells.

Mitogen activated protein kinase 6 and MAP kinase phosphatase 1 are involved in the response of Arabidopsis roots to l-glutamate

2018 ◽  
Vol 96 (4-5) ◽  
pp. 339-351 ◽  
Author(s):  
Jesús Salvador López-Bucio ◽  
Javier Raya-González ◽  
Gustavo Ravelo-Ortega ◽  
León Francisco Ruiz-Herrera ◽  
Maricela Ramos-Vega ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Map Kinase Phosphatase ◽  
Mitogen Activated Protein
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