Conformation-dependent activation of type II adenylyl cyclase by protein kinase C

Author(s):  
Toshiaki Ebina ◽  
Jun-ichi Kawabe ◽  
Toshiaki Katada ◽  
Shigeo Ohno ◽  
Charles J. Homcy ◽  
...  
Bone ◽  
1996 ◽  
Vol 18 (1) ◽  
pp. 59-65 ◽  
Author(s):  
M. Sabatini ◽  
C. Lesur ◽  
M. Pacherie ◽  
P. Pastoureau ◽  
N. Kucharczyk ◽  
...  

2010 ◽  
Vol 299 (5) ◽  
pp. H1459-H1467 ◽  
Author(s):  
Valeriy Timofeyev ◽  
Cliff A. Porter ◽  
Dipika Tuteja ◽  
Hong Qiu ◽  
Ning Li ◽  
...  

Adenylyl cyclase (AC) is the principal effector molecule in the β-adrenergic receptor pathway. ACV and ACVI are the two predominant isoforms in mammalian cardiac myocytes. The disparate roles among AC isoforms in cardiac hypertrophy and progression to heart failure have been under intense investigation. Specifically, the salutary effects resulting from the disruption of ACV have been established in multiple models of cardiomyopathy. It has been proposed that a continual activation of ACV through elevated levels of protein kinase C could play an integral role in mediating a hypertrophic response leading to progressive heart failure. Elevated protein kinase C is a common finding in heart failure and was demonstrated in murine cardiomyopathy from cardiac-specific overexpression of Gαq protein. Here we assessed whether the disruption of ACV expression can improve cardiac function, limit electrophysiological remodeling, or improve survival in the Gαq mouse model of heart failure. We directly tested the effects of gene-targeted disruption of ACV in transgenic mice with cardiac-specific overexpression of Gαq protein using multiple techniques to assess the survival, cardiac function, as well as structural and electrical remodeling. Surprisingly, in contrast to other models of cardiomyopathy, ACV disruption did not improve survival or cardiac function, limit cardiac chamber dilation, halt hypertrophy, or prevent electrical remodeling in Gαq transgenic mice. In conclusion, unlike other established models of cardiomyopathy, disrupting ACV expression in the Gαq mouse model is insufficient to overcome several parallel pathophysiological processes leading to progressive heart failure.


1998 ◽  
Vol 275 (2) ◽  
pp. F270-F277 ◽  
Author(s):  
Eleanor D. Lederer ◽  
Sameet S. Sohi ◽  
Jeanine M. Mathiesen ◽  
Jon B. Klein

The purpose of the present study was to determine the effect of protein kinase A and protein kinase C activation on the membrane expression of NaPi-4, the type II sodium-phosphate cotransporter in OK cells. NaPi-4 expression was measured using polyclonal antisera produced in rabbits against a peptide identical to the carboxy-terminal 12-amino acid sequence of NaPi-4. The antisera identified an apically localized protein by confocal imaging of intact OK cells and a broad band of 110–140 kDa by immunoblot analysis of OK cell membranes. Treatment of OK cells with parathyroid hormone (PTH) decreased the intensity of the 110- to 140-kDa band, which was detectable by 2 h, maximal by 4 h at 62%, and sustained for 24 h. 8-Bromo-cAMP (8-BrcAMP) inhibited NaPi-4 expression for up to 24 h by over 90%. However, phorbol 12-myristate 13-acetate inhibited NaPi-4 expression by less than 10%. PTH-(3–34), a fragment which stimulates only protein kinase C, inhibited phosphate transport but also had no effect on NaPi-4 expression. We conclude that protein kinase A but not protein kinase C inhibits sodium-phosphate uptake in OK cells by downregulation of NaPi-4 expression.


1991 ◽  
Vol 112 (6) ◽  
pp. 1241-1247 ◽  
Author(s):  
N Usuda ◽  
Y Kong ◽  
M Hagiwara ◽  
C Uchida ◽  
M Terasawa ◽  
...  

We report the immunohistochemical localization of protein kinase C isozymes (types I, II, and III) in the rabbit retina using the monospecific monoclonal antibodies MC-1a, MC-2a, and MC-3a. Using immunoblot analysis of partially purified protein kinase C preparations of rabbit retina, types II and III isozymes alone were detected. The activity of type III was the stronger. By light microscopic immunohistochemical analysis, retinal neurons were negative for type I and positive for type II and type III isozymes. Type II was more diffusely distributed through the retinal layers, but was distinctive in ganglion cells, bipolar cells, and outer segments. The immunoreactivity was stronger for type III isozyme, and it was observed in mop (rod) bipolar cells and amacrine cells. By using immunoelectron microscopy, the cytoplasm of the cell body, the axon, and dendrites of the mop bipolar cells were strongly immunoreactive for type III. The so-called rod bipolar cells were for the first time seen to form synapses with rod photoreceptor cells. These differential localizations of respective isozymes in retinal neurons suggest that each isozyme has a different site of function in each neuron.


1991 ◽  
Vol 261 (4) ◽  
pp. L105-L109
Author(s):  
T. A. Voyno-Yasenetskaya ◽  
L. G. Dobbs ◽  
M. C. Williams

Several different classes of agonists are known to stimulate exocytosis in type II cells. These agonists cause increases in second messengers, such as adenosine 3',5'-cyclic monophosphate (cAMP) or cytosolic Ca2+, and/or stimulate protein kinase C. We studied generation of cAMP and phosphoinositide (PI) turnover in monolayer cultures of type II cells and measured [Ca2+]i in single cultured cells. ATP [10-4 M], which stimulates secretion of phosphatidylcholine (PC) and increases cellular cAMP, also stimulated PI turnover and increased [Ca2+]i. 12-O-tetradecanoylphorbol-13-acetate (TPA), which stimulates PC secretion and activates protein kinase C, did not increase [Ca2+]i. Pretreatment of type II cells with the calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) inhibited the PC secretion induced by ATP and TPA and blocked the increase in PI turnover caused by ATP. ATP-dependent surfactant secretion and stimulation of PI turnover could also be inhibited by pretreatment of the cells with pertussis toxin. We used the fluorescent probe indo-1 to measure [Ca2+]i in single cultured type II cells. ATP produced rapid transient increases in [Ca2+]i, which could be prevented by pretreatment of the cells with either TPA or W-7. Our data suggest that pertussis toxin-sensitive G protein(s) are involved in ATP-dependent activation of PI turnover and in secretion of surfactant in type II cells. Activation of protein kinase C blocks the ATP-stimulated increase in [Ca2+]i. Finally, calmodulin may be involved in the regulation of ATP-dependent increase in [Ca2+]i, the activation of PI turnover, and the secretion of surfactant in type II cells. lung; exocytosis; cell calcium; G proteins; phosphoinositide turnover


1994 ◽  
Vol 266 (6) ◽  
pp. E897-E904 ◽  
Author(s):  
A. M. Kitten ◽  
T. K. Hymer ◽  
M. S. Katz

The temporal pattern with which phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C (PKC), modulates parathyroid hormone (PTH)-responsive adenylyl cyclase (AC) was evaluated in a clonal osteoblast-like cell line (UMR-106). Brief (< or = 1 h) exposure of UMR-106 cells to PMA enhanced PTH stimulation of AC, whereas more prolonged PMA treatment decreased the PTH response, with maximum inhibition occurring at < or = 6 h. PMA treatment also resulted in initial activation followed by downregulation of PKC. Exposure of cells to 1,2-dioctanoyl-sn-glycerol, which activated but did not downregulate PKC, resulted in bidirectional modulation of PTH-responsive AC identical to that produced by PMA. Prolonged PMA exposure decreased PTH receptor number, as determined by radioligand binding studies, and reduced PTH receptor mRNA levels, assessed by Northern blot analysis. Forskolin activation of the catalytic subunit of AC was also decreased after prolonged PMA treatment. The results suggest that activation of PKC sequentially stimulates and then inhibits PTH responsiveness. Inhibition of the PTH response occurs by PKC actions exerted on the PTH receptor and the AC catalytic subunit.


1992 ◽  
Vol 284 (2) ◽  
pp. 399-405 ◽  
Author(s):  
K J Balazovich ◽  
E L McEwen ◽  
M L Lutzke ◽  
L A Boxer ◽  
T White

Human neutrophil protein kinase C (PKC) activity is inhibited by an endogenous protein found primarily in the pellet fraction from homogenized specific granules, which was both heat- and proteinase-sensitive [Balazovich, Smolen & Boxer (1986) J. Immunol. 137, 1665-1673]. We now report that two PKC isoenzymes and the endogenous PKC inhibitor, which we named PKC-I, were purified from human neutrophils. A neutrophil soluble fraction that was subjected to DEAE-Sephacel chromatography yielded highly enriched PKC because, by definition, enzymic activity was strictly dependent on Ca2+ and phosphatidylserine. Hydroxyapatite chromatography resolved two peaks of PKC activity. Type II and Type III PKC isoenzymes were each identified on Western blots by using isoenzyme-specific monoclonal antibodies. Unlike rat brain, from which PKC isoenzymes were also purified, Type I PKC was not detected in human neutrophils. Western blots indicated that both Type II and Type III PKC isoenzymes had molecular masses near 80 kDa. In agreement with other reports, PKC was autophosphorylated in vitro. PKC-I, an endogenous neutrophil inhibitor of PKC, was purified to apparent homogeneity by DEAE-Sephacel and S-400 Sephacel chromatography. PKC-I had a molecular mass of 41 kDa. PKC-I inhibited purified PKC activity stimulated by 1,2-diacylglycerols in a concentration-dependent manner, and inhibited PKC-dependent phosphorylation of proteins present in neutrophil cytosol.


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