Roles of Ca2+ and protein kinase C in the excitatory response to serotonin in embryonic molluscan ciliary cells

2006 ◽  
Vol 84 (6) ◽  
pp. 635-646 ◽  
Author(s):  
Shandra A. Doran ◽  
Jeffrey I. Goldberg

We examined the roles of Ca2+ and protein kinase C (PKC) in the cilio-excitatory response to serotonin in pedal ciliary cells from Helisoma trivolvis embryos. Serotonin (5-hydroxytryptamine; 5-HT; 100 µmol/L) induced an increase in ciliary beat frequency (CBF) was abolished by microinjected BAPTA (50 mmol/L), but was only partially inhibited by the phospholipase C inhibitor U-73122 (10 µmol/L). The diacylglycerol analogs 1-oleoyl-2-acetyl-sn-glycerol (100 µmol/L) and 1,2-dioctanoyl-sn-glycerol (100 µmol/L) caused increases in [Ca2+]i that were smaller than those induced by serotonin. In the absence of extracellular Ca2+, 1,2-dioctanoyl-sn-glycerol (100 µmol/L) failed to elicit an increase in both CBF and [Ca2+]i. In contrast, the serotonin-induced increase in CBF persisted in the absence of extracellular Ca2+, although the increase in [Ca2+]i was abolished. PKC inhibitors bisindolylmaleimide (10 and 100 nmol/L) and calphostin C (10 nmol/L) partially inhibited the serotonin-induced increase in CBF, but didn’t affect the serotonin-induced change in [Ca2+]i. These findings suggest that an intracellular store-dependent increase in [Ca2+]i mediates the cilio-excitatory response to serotonin. Furthermore, although PKC is able to cause an increase in [Ca2+]i through calcium influx, it contributes to the cilio-excitatory response to 5-HT through a different mechanism.

1993 ◽  
Vol 106 (4) ◽  
pp. 1211-1220
Author(s):  
M. Salathe ◽  
M.M. Pratt ◽  
A. Wanner

The present study examined whether protein kinase C phosphorylated a ciliary protein and whether this phosphorylation event was temporally correlated with a decrease in ciliary beat frequency. Activation of protein kinase C decreased ciliary beat frequency of sheep tracheal epithelium, an effect fully blockable by pretreatment of the tissue pieces with H-7, a protein kinase inhibitor. Using cilia removed from these epithelial surfaces and incubated in solutions containing stimulators of protein kinase C along with [gamma-32P]ATP or [gamma-35S]ATP, a single protein target of ciliary protein kinase C activity was identified. The protein is a polypeptide of molecular mass 37 kDa (p37) as estimated by SDS-polyacrylamide gel electrophoresis. Protein kinase C dependency of p37 phosphorylation was proven by showing that Calphostin C, a specific protein kinase C inhibitor, blocked label incorporation into p37 completely, and by demonstrating that purified protein kinase C phosphorylated p37. Inhibitors of cAMP-dependent kinase and calcium/calmodulin-dependent kinase did not change the phosphorylation of p37 in the presence of protein kinase C activators. p37 was recovered in a Triton X-100-extractable fraction of this ciliary preparation, suggesting that p37 is membrane associated. This hypothesis was further supported by the fact that p37 was present in a pellet representing reconstituted membranes. Thin-layer electrophoresis revealed that p37 was phosphorylated on serine and tyrosine residues, suggesting that the activation of protein kinase C also stimulated tyrosine kinase activity. p37 did not precipitate with annexin I or II antibodies. These results show that sheep tracheal cilia contain protein kinase C activity and that activated protein kinase C phosphorylates a membrane-associated ovine ciliary target, an effect temporally related to a protein kinase C-mediated decrease in ciliary beat frequency.


2000 ◽  
Vol 13 (3) ◽  
pp. 273-279 ◽  
Author(s):  
XOWI K.M.S. MWIMBI ◽  
RICHMOND MUIMO ◽  
MICHAEL GREEN ◽  
ANIL MEHTA

1999 ◽  
Vol 274 (36) ◽  
pp. 25525-25534 ◽  
Author(s):  
Isamu Okamoto ◽  
Yoshiaki Kawano ◽  
Mitsuhiro Matsumoto ◽  
Moritaka Suga ◽  
Kozo Kaibuchi ◽  
...  

2001 ◽  
Vol 280 (4) ◽  
pp. R968-R975 ◽  
Author(s):  
Michelle Rapacon-Baker ◽  
Fan Zhang ◽  
Michael L. Pucci ◽  
Hui Guan ◽  
Alberto Nasjletti

We investigated the effect of intraluminal pressure or stretch on the development of tone in the descending thoracic aorta from rats with aortic coarctation-induced hypertension of 7–14 days duration. Increments of pressure >100 mmHg decreased the diameter of thoracic aortas from hypertensive but not from normotensive rats. The pressure-induced constriction was not demonstrable in vessels superfused with calcium-free buffer. Stretched rings of aorta from hypertensive rats exhibited a calcium-dependent constrictor tone accompanied by elevated calcium influx that varied in relation to the degree of stretch. Blockers of l-type calcium channels and inhibitors of protein kinase C reduced both basal tone and calcium influx in aortic rings of hypertensive rats. Hence, the thoracic aorta of hypertensive rats expresses a pressure- and stretch-activated constrictor mechanism that relies on increased calcium influx throughl-type calcium channels via a protein kinase C-regulated pathway. The expression of such a constrictor mechanism is suggestive of acquired myogenic behavior.


1992 ◽  
Vol 76 (1) ◽  
pp. 111-118 ◽  
Author(s):  
Nobutaka Minami ◽  
Eiichi Tani ◽  
Yukio Maeda ◽  
Ikuya Yamaura ◽  
Masahiro Fukami

✓ Vasospasm was produced in adult mongrel dogs by a two-hemorrhage method, and the spastic basilar arteries were exposed via the transclival route on Day 7. Tonic contraction was produced in the normal canine basilar arteries by a local application of KCl or serotonin after transclival exposure. The exposed spastic and tonic basilar arteries then received a topical application of the following: 1-(5-isoquinolinesulfonyl)-2-methyl-piperazine (H-7), a potent inhibitor of protein kinase C acting at the catalytic domain; calphostin C, a specific inhibitor of protein kinase C acting at the regulatory domain; or calpeptin, a selective inhibitor of calpain. Both spastic and tonic basilar arteries were effectively dilated by H-7. Calphostin C caused only slight dilation of spastic basilar arteries but moderate dilation of tonic basilar arteries. Dilation in response to calpeptin was remarkable in the spastic basilar arteries but slight in the tonic basilar arteries. The doses of calphostin C and calpeptin required to obtain maximum effect were markedly lower in the tonic model than in the spastic model. The spastic and tonic models had a similar dose-dependent response to H-7 but quite a different response to calphostin C or calpeptin, suggesting a difference in the function of protein kinase C and calpain in the two models. Furthermore, the effect of calphostin C on the reversal of vasospasm was increased significantly after topical treatment with calpeptin. It is suggested that the majority of the catalytic domain of protein kinase C is dissociated from the regulatory domain, probably by a limited proteolysis with calpain, and is markedly activated in vasospasm.


1997 ◽  
Vol 273 (5) ◽  
pp. L1007-L1012 ◽  
Author(s):  
Todd A. Wyatt ◽  
Harumasa Ito ◽  
Thomas J. Veys ◽  
John R. Spurzem

Bronchial epithelial cell migration, attachment, and proliferation are important processes in response to airway injury. We have shown that tumor necrosis factor (TNF)-α stimulates the migration of bovine bronchial epithelial cells (BBEC) in vitro. We hypothesized that protein kinase C (PKC) may be one of the intracellular signaling mediators of TNF-α in BBEC. In this study, we have identified multiple PKC isoforms in BBEC and measured total cellular PKC activity. Polyclonal antibodies to the PKC-α, -β2, -δ, and -ε isoforms recognized protein bands around 80–90 kDa. BBEC primary cultures treated with either 500 U/ml TNF-α for 2–4 h or 100 ng/ml 12- O-tetradecanoylphorbol 13-acetate for 15 min resulted in three- to fivefold increases in PKC activity in the particulate fractions of crude cell lysates. This activity was inhibited by 1 μM calphostin C or 10 μM H-7. Similarly, TNF-α-stimulated BBEC migration was reduced at least twofold in the presence of H-7 or calphostin C. These studies suggest that the activation of PKC is necessary for TNF-α-stimulated BBEC migration.


1993 ◽  
Vol 264 (4) ◽  
pp. H1300-H1306 ◽  
Author(s):  
Y. Shimamoto ◽  
H. Shimamoto ◽  
C. Y. Kwan ◽  
E. E. Daniel

We investigated effects of three kinds of putative protein kinase C (PKC) inhibitors, calphostin C, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), and stauro-sporine, on aortic muscle contractions induced by KCl, phenylephrine, 12-O-tetradecanoylphorbol-13-acetate (TPA), and phorbol 12, 13-dibutyrate (PDBu). Calphostin C noncompetitively inhibited TPA-induced contractions in a concentration-dependent manner. At 10(-6) M, calphostin C completely abolished responses to TPA and also effectively inhibited PDBu-induced contractions. Such a concentration of calphostin C had no effect on KCl-induced contractions but decreased the maximal tension of phenylephrine-induced response curve by 35.3 +/- 6.6% H-7 (10(-5) M had little effect on TPA-induced contraction but significantly inhibited contractile responses to phenylephrine and KCl. Staurosporine (10(-8) M, 3 x 10(-8) M) inhibited contractile responses to KCl, phenylephrine, and TPA. We suggest that staurosporine and H-7, which are known to act on the catalytic domain of PKC carrying high degree of sequence homology with other protein kinases, are relatively nonselective for PKC. On the other hand, calphostin C acting on the regulatory domain of PKC, which is distinct from other protein kinases, may serve as a relatively more selective PKC inhibitor.


2002 ◽  
Vol 70 (5) ◽  
pp. 2112-2119 ◽  
Author(s):  
Ana Luísa Carvalho ◽  
Carlos B. Duarte ◽  
Carlos J. Faro ◽  
Arsélio P. Carvalho ◽  
Euclides V. Pires

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