scholarly journals Rac1 is a downstream effector of PKCα in structural synaptic plasticity

2019 ◽  
Author(s):  
Xun Tu ◽  
Ryohei Yasuda ◽  
Lesley A Colgan
Keyword(s):  
Dendritic Spines ◽  
Structural Plasticity ◽  
Small Gtpases ◽  
Functional Plasticity ◽  
Dependent Protein Kinase ◽  
Calcium Dependent ◽  
Downstream Effector ◽  
Kinase C ◽  
Dependent Protein ◽  
Calcium Dependent Protein Kinase

AbstractStructural and functional plasticity of dendritic spines is the basis of animal learning. The calcium-dependent protein kinase C isoform, PKCα, has been suggested to be critical for this actin-dependent plasticity. However, mechanisms linking PKCα and structural plasticity of spines are unknown. Here, we examine the spatiotemporal activation of actin regulators, including small GTPases Rac1, Cdc42 and Ras, in the presence or absence of PKCα during single-spine structural plasticity. Removal of PKCα expression in the postsynapse attenuated Rac1 activation during structural plasticity without affecting Ras or Cdc42 activity. Moreover, disruption of a PDZ binding domain within PKCα led to impaired Rac1 activation and deficits in structural spine remodeling. These results demonstrate that PKCα positively regulates the activation of Rac1 during structural plasticity.

Calcium-dependent Protein Kinase Reactions Associated with Parotid Gland Secretory Granule Membranes

1987 ◽  
Vol 66 (2) ◽  
pp. 557-563 ◽  
Author(s):  
F. Dowd ◽  
E.L. Watson ◽  
Y.-S. Lau ◽  
J. Justin ◽  
J. Pasieniuk ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Secretory Granule ◽  
Dependent Protein Kinase ◽  
Calcium Dependent ◽  
Kinase C ◽  
Protein Kinase C Activity ◽  
Granule Membrane ◽  
Dependent Protein ◽  
Calcium Dependent Protein Kinase

Rat parotid secretory granule membranes were examined for the presence of calcium-dependent protein kinase activities and kinase substrates. Protein kinase C (C-kinase), which is stimulated by certain phospholipids, was present in the membranes, as indicated by its ability to catalyze the phosphorylation of histone. Two substrates for protein kinase C were seen in the granule membranes. The cytosolic fraction from the cell contained kinase activity, which was stimulated by phosphatidylserine and which caused the phosphorylation of two granule membrane polypeptides. In addition, when both granule membranes and cytosol were incubated together, phosphorylation of the cytosolic substrates was inhibited, indicating that the granule membrane substrates were phosphorylated preferentially. The results indicate that the granule membranes may react with cytosolic protein kinase C activity in a way which would direct an intracellular calcium and diacylglycerol signal toward the granule membrane. Since these signals occur during stimulation by various agonists, the mechanism may contribute to secretion.

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