The diverse roles of protein kinase C in pancreatic β-cell function

2008 ◽  
Vol 36 (5) ◽  
pp. 916-919 ◽  
Author(s):  
Trevor J. Biden ◽  
Carsten Schmitz-Peiffer ◽  
James G. Burchfield ◽  
Ebru Gurisik ◽  
James Cantley ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cell Function ◽  
Cell Types ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Surface Receptors ◽  
Kinase C ◽  
Pkc Isoforms ◽  
Β Cell Function

Members of the serine/threonine PKC (protein kinase C) family perform diverse functions in multiple cell types. All members of the family are activated in signalling cascades triggered by occupation of cell surface receptors, but the cPKC (conventional PKC) and nPKC (novel PKC) isoforms are also responsive to fatty acid metabolites. PKC isoforms are involved in various aspects of pancreatic β-cell function, including cell proliferation, differentiation and death, as well as regulation of secretion in response to glucose and muscarinic receptor agonists. Recently, the nPKC isoform, PKCϵ, has also been implicated in the loss of insulin secretory responsiveness that underpins the development of Type 2 diabetes.

Adipokines as key players in β cell function and failure

2019 ◽  
Vol 133 (22) ◽  
pp. 2317-2327 ◽  
Author(s):  
Nicolás Gómez-Banoy ◽  
James C. Lo
Keyword(s):  
Metabolic Diseases ◽  
Cell Function ◽  
Whole Body ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Cell Axis ◽  
Β Cell Function ◽  
Prevalence Of Obesity ◽  
Specific Factors ◽  
Whole Body Metabolism

Abstract The growing prevalence of obesity and its related metabolic diseases, mainly Type 2 diabetes (T2D), has increased the interest in adipose tissue (AT) and its role as a principal metabolic orchestrator. Two decades of research have now shown that ATs act as an endocrine organ, secreting soluble factors termed adipocytokines or adipokines. These adipokines play crucial roles in whole-body metabolism with different mechanisms of action largely dependent on the tissue or cell type they are acting on. The pancreatic β cell, a key regulator of glucose metabolism due to its ability to produce and secrete insulin, has been identified as a target for several adipokines. This review will focus on how adipokines affect pancreatic β cell function and their impact on pancreatic β cell survival in disease contexts such as diabetes. Initially, the “classic” adipokines will be discussed, followed by novel secreted adipocyte-specific factors that show therapeutic promise in regulating the adipose–pancreatic β cell axis.

scholarly journals Bace2 Is a β Cell-Enriched Protease that Regulates Pancreatic β Cell Function and Mass

2011 ◽  
Vol 14 (3) ◽  
pp. 365-377 ◽  
Author(s):  
Daria Esterházy ◽  
Ina Stützer ◽  
Haiyan Wang ◽  
Markus P. Rechsteiner ◽  
Jeremy Beauchamp ◽  
...  
Keyword(s):  
Cell Function ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Β Cell Function

Relationship between Protein kinase C isoforms, Telomerase and Alpha- fetoprotein through PI3K/AKT/mTOR pathway in Hepatocellular carcinoma

MedPharmRes ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 12-26
Author(s):  
Rita Ammoury ◽  
Roula Tahtouh ◽  
Nadine Mahfouz ◽  
Raia Doumit ◽  
Charbel Khalil ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Telomerase Activity ◽  
Mtor Pathway ◽  
Alpha Fetoprotein ◽  
Mrna Levels ◽  
Htert Expression ◽  
Kinase C ◽  
Pkc Isoforms

Protein kinase C (PKC) family has been an alluring objective for new cancer drug discovery. It has been reported to regulate telomerase in several cancer types. Our team had previously used telomerase to elucidate alpha-fetoprotein (AFP) modulation in hepatocellular carcinoma (HCC). The aim of this study was to investigate the interrelationships among PKC isoforms, telomerase and AFP in HCC. PKCα and PKCδ were the most expressed isoforms in HepG2/C3A, PLC/PRF/5, SNU-387 and SKOV-3 cells. Following the upregulation of AFP using pCMV3-AFP and the human telomerase reverse transcriptase (hTERT) using a construct expressing a wild-type hTERT, and after their inhibition with all-trans retinoic acid and hTERT siRNA each respectively, we found that the expression of PKCα, PKCβI, PKCβII and PKCδ was affected by the variation of AFP and hTERT mRNA levels. An increase in AFP expression and secretion was observed after gene silencing of PKCα, PKCβ, PKCδ, and PKCε in HepG2/C3A. A similar pattern was observed in transfected PLC/PRF/5 cells, however PKCδ isoform silencing decreased AFP expression. Furthermore, telomerase activity was quantified using quantitative telomeric repeat amplification protocol. The variations in hTERT expression and telomerase activity were similar to those of AFP. Further investigation showed that PKC isoforms regulate AFP and hTERT expression levels through PI3K/AKT/mTOR pathway in HepG2/C3A and PLC/PRF/5 cells. Thus, these results show for the first time a possible interrelationship that links PKC isoforms to both AFP and hTERT via PI3K/AKT/mTOR pathway in HCC.

Protein kinase C-α and the regulation of diverse cell responses

2017 ◽  
Vol 8 (3-4) ◽  
pp. 143-153 ◽  
Author(s):  
Rishi Kant Singh ◽  
Sanjay Kumar ◽  
Pramod Kumar Gautam ◽  
Munendra Singh Tomar ◽  
Praveen Kumar Verma ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cellular Localization ◽  
Cellular Transformation ◽  
Cell Types ◽  
Adapter Proteins ◽  
Cellular Functions ◽  
Cell Responses ◽  
Kinase C ◽  
Cellular Compartments

AbstractProtein kinase C (PKC) comprises a family of lipid-sensitive enzymes that have been involved in a broad range of cellular functions. PKC-α is a member of classical PKC with ubiquitous expression and different cellular localization. This unique PKC isoform is activated by various signals which evoke lipid hydrolysis, after activation it interacts with various adapter proteins and is localized to specific cellular compartments where it is devised to work. The universal expression and activation by various stimuli make it a perfect player in uncountable cellular functions including differentiation, proliferation, apoptosis, cellular transformation, motility, adhesion and so on. However, these functions are not intrinsic properties of PKC-α, but depend on cell types and conditions. The activities of PKC-α are managed by the various pharmacological activators/inhibitors and antisense oligonucleotides. The aim of this review is to elaborate the structural feature, and provide an insight into the mechanism of PKC-α activation and regulation of its key biological functions in different cellular compartments to develop an effective pharmacological approach to regulate the PKC-α signal array.

Mechanism of Hepatic Heme Oxygenase-1 Induction by Isoflurane

2006 ◽  
Vol 104 (1) ◽  
pp. 101-109 ◽  
Author(s):  
Alexander Hoetzel ◽  
Daniel Leitz ◽  
Rene Schmidt ◽  
Eva Tritschler ◽  
Inge Bauer ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase A2 ◽  
Heme Oxygenase ◽  
Kupffer Cell ◽  
Cell Function ◽  
Heme Oxygenase 1 ◽  
Gadolinium Chloride ◽  
Kinase C

Background The heme oxygenase pathway represents a major cell and organ protective system in the liver. The authors recently showed that isoflurane and sevoflurane up-regulate the inducible isoform heme oxygenase 1 (HO-1). Because the activating cascade remained unclear, it was the aim of this study to identify the underlying mechanism of this effect. Methods Rats were anesthetized with pentobarbital intravenously or with isoflurane per inhalation (2.3 vol%). Kupffer cell function was inhibited by dexamethasone or gadolinium chloride. Nitric oxide synthases were inhibited by either N(omega)-nitro-L-arginine methyl ester or S-methyl thiourea. N-acetyl-cysteine served as an antioxidant, and diethyldithiocarbamate served as an inhibitor of cytochrome P450 2E1. Protein kinase C and phospholipase A2 were inhibited by chelerythrine or quinacrine, respectively. HO-1 was analyzed in liver tissue by Northern blot, Western blot, immunostaining, and enzymatic activity assay. Results In contrast to pentobarbital, isoflurane induced HO-1 after 4-6 h in hepatocytes in the pericentral region of the liver. The induction was prevented in the presence of dexamethasone (P < 0.05) and gadolinium chloride (P < 0.05). Inhibition of nitric oxide synthases or reactive oxygen intermediates did not affect isoflurane-mediated HO-1 up-regulation. In contrast, chelerythrine (P < 0.05) and quinacrine (P < 0.05) resulted in a blockade of HO-1 induction. Conclusion The up-regulation of HO-1 by isoflurane in the liver is restricted to parenchymal cells and depends on Kupffer cell function. The induction is independent of nitric oxide or reactive oxygen species but does involve protein kinase C and phospholipase A2.

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