scholarly journals Novel Protein Kinase C δ Isoform Insensitive to Caspase-3

2001 ◽  
Vol 24 (9) ◽  
pp. 973-977 ◽  
Author(s):  
Yoshiaki SAKURAI ◽  
Yoshiaki ONISHI ◽  
Yutaka TANIMOTO ◽  
Harutoshi KIZAKI
2008 ◽  
Vol 28 (15) ◽  
pp. 4719-4733 ◽  
Author(s):  
Carole A. Farah ◽  
Ikue Nagakura ◽  
Daniel Weatherill ◽  
Xiaotang Fan ◽  
Wayne S. Sossin

ABSTRACT In Aplysia californica, the serotonin-mediated translocation of protein kinase C (PKC) Apl II to neuronal membranes is important for synaptic plasticity. The orthologue of PKC Apl II, PKCε, has been reported to require phosphatidic acid (PA) in conjunction with diacylglycerol (DAG) for translocation. We find that PKC Apl II can be synergistically translocated to membranes by the combination of DAG and PA. We identify a mutation in the C1b domain (arginine 273 to histidine; PKC Apl II-R273H) that removes the effects of exogenous PA. In Aplysia neurons, the inhibition of endogenous PA production by 1-butanol inhibited the physiological translocation of PKC Apl II by serotonin in the cell body and at the synapse but not the translocation of PKC Apl II-R273H. The translocation of PKC Apl II-R273H in the absence of PA was explained by two additional effects of this mutation: (i) the mutation removed C2 domain-mediated inhibition, and (ii) the mutation decreased the concentration of DAG required for PKC Apl II translocation. We present a model in which, under physiological conditions, PA is important to activate the novel PKC Apl II both by synergizing with DAG and removing C2 domain-mediated inhibition.


2014 ◽  
Vol 34 (9) ◽  
pp. 869-877 ◽  
Author(s):  
ES Son ◽  
SY Kyung ◽  
SP Lee ◽  
SH Jeong ◽  
JY Shin ◽  
...  

Cigarette smoke (CS) is a major risk factor for emphysema, which causes cell death in structural cells of the lung by mechanisms that are still not completely understood. We demonstrated previously that CS extract (CSE) induces caspase activation in MRC-5 human lung fibroblasts, activated protein kinase C-η (PKC-η), and translocated PKC-η from the cytosol to the membrane. The objective of this study was to investigate the involvement of PKC-η activation in a CSE-induced extrinsic apoptotic pathway. We determined that CSE increases expression of caspase 3 and 8 cleavage in MRC-5 cells and overexpression of PKC-η significantly increased expression of caspase 3 and 8 cleavage compared with control LacZ-infected cells. In contrast, dominant negative (dn) PKC-η inhibited apoptosis in MRC-5 cells exposed to CSE and decreased expression of caspase 3 and 8 compared with control cells. Exposure to 10% CSE for >8 h significantly increased lactate dehydrogenase release in PKC-η-infected cells compared with LacZ-infected cells. Additionally, PKC-η-infected cells had an increased number of Hoechst 33342 stained nuclei compared with LacZ-infected cells, while dn PKC-η-infected cells exhibited fewer morphological changes than LacZ-infected cells under phase-contrast microscopy. In conclusion, PKC-η activation plays a pro-apoptotic role in CSE-induced extrinsic apoptotic pathway in MRC-5 cells. These results suggest that modulation of PKC-η may be a useful tool for regulating the extrinsic apoptosis of MRC-5 cells by CSE and may have therapeutic potential in the treatment of CS-induced lung injury.


Phytomedicine ◽  
2019 ◽  
Vol 65 ◽  
pp. 153100 ◽  
Author(s):  
Yuwei Wang ◽  
Chunping Tang ◽  
Sheng Yao ◽  
Huanling Lai ◽  
Runze Li ◽  
...  

2009 ◽  
Vol 297 (6) ◽  
pp. H2253-H2261 ◽  
Author(s):  
Kaori Kato ◽  
Dai Yamanouchi ◽  
Karla Esbona ◽  
Kentaro Kamiya ◽  
Fan Zhang ◽  
...  

Apoptotic death of vascular smooth muscle cells (SMCs) is a prominent feature of blood vessel remodeling and various vascular diseases. We have previously shown that protein kinase C-δ (PKC-δ) plays a critical role in SMC apoptosis. In this study, we tested the importance of PKC-δ proteolytic cleavage and tyrosine phosphorylation within the apoptosis pathway. Using hydrogen peroxide as a paradigm for oxidative stress, we showed that proteolytic cleavage of PKC-δ occurred in SMCs that underwent apoptosis, while tyrosine phosphorylation was detected only in necrotic cells. Furthermore, using a peptide (z-DIPD-fmk) that mimics the caspase-3 binding motif within the linker region of PKC-δ, we were able to prevent the cleavage of PKC-δ, as well as apoptosis. Inhibition of PKC-δ with rottlerin or small-interfering RNA diminished caspase-3 cleavage, caspase-3 activity, cleavage of poly (ADP-ribose) polymerase, cleavage of PKC-δ, and DNA fragmentation, confirming the previously reported role of PKC-δ in initiation of apoptosis. In contrast, z-DIPD-fmk markedly diminished caspase-3 activity, cleavage of PKC-δ, and DNA fragmentation without affecting cleavage of caspase-3 and poly (ADP-ribose) polymerase. Taken together, our data suggest that caspase-3-mediated PKC-δ cleavage underlies SMC apoptosis induced by oxidative stress, and that PKC-δ acts both upstream and downstream of caspase-3.


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