A dual mechanism for regulation of kidney phosphate transport by parathyroid hormone

1987 ◽  
Vol 253 (2) ◽  
pp. E221-E227 ◽  
Author(s):  
J. A. Cole ◽  
S. L. Eber ◽  
R. E. Poelling ◽  
P. K. Thorne ◽  
L. R. Forte
Keyword(s):  
Protein Kinase C ◽  
Parathyroid Hormone ◽  
Protein Kinase ◽  
Phorbol Esters ◽  
Rank Order ◽  
Phosphate Transport ◽  
Opossum Kidney ◽  
Ok Cells ◽  
Kinase C ◽  
Camp Formation

Regulation of phosphate transport by parathyroid hormone (PTH) was investigated in continuous lines of kidney cells. Phosphate transport was reduced by PTH-(1-34) at physiological concentrations (EC50 5 X 10(-11) M), whereas much higher concentrations were required to stimulate cAMP formation (EC50 1 X 10(-8) M) in opossum kidney (OK) cells. The PTH analogue [Nle]PTH-(3-34) also inhibited phosphate transport but did not enhance cAMP formation. Instead, [Nle]PTH-(3-34) was a competitive antagonist of PTH-(1-34) at cyclase-coupled receptors. PTH-(7-34) had no effect on phosphate transport or cAMP formation. Phorbol esters or mezerein were potent inhibitors of phosphate transport but did not affect cAMP synthesis. Their potencies paralleled the rank-order potency of these agents as activators of protein kinase c in other systems. Maximally effective concentrations of PTH-(1-34) and mezerein did not produce additive inhibition of phosphate transport in OK cells. Phorbol esters stimulated phosphate transport in JTC-12 cells, but PTH-(1-34) had no effect. We concluded that PTH regulates OK cell phosphate transport by interacting with two classes of receptors, and transmembrane-signaling mechanisms. Physiological levels of PTH-(1-34) may regulate phosphate transport by activation of protein kinase c, whereas higher concentrations appear to activate adenylate cyclase.

Inhibition of PAH transport by parathyroid hormone in OK cells: involvement of protein kinase C pathway

1997 ◽  
Vol 273 (5) ◽  
pp. F674-F679 ◽  
Author(s):  
Junya Nagai ◽  
Ikuko Yano ◽  
Yukiya Hashimoto ◽  
Mikihisa Takano ◽  
Ken-Ichi Inui
Keyword(s):  
Protein Kinase C ◽  
Parathyroid Hormone ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Regulatory Control ◽  
Dependent Manner ◽  
Transcellular Transport ◽  
Ok Cells ◽  
Kinase C ◽  
Kinase A

We have previously shown that the p-aminohippurate (PAH) transport system in OK kidney epithelial cell line is under the regulatory control of protein kinase C. Parathyroid hormone (PTH) could activate protein kinase C, as well as protein kinase A, in OK cells. In the present study, the effect of PTH on PAH transport was studied in OK cells. PTH inhibited the transcellular transport of PAH from the basal to the apical side, as well as the accumulation of PAH in OK cells. Basolateral PAH uptake was inhibited by PTH in a dose- and time-dependent manner. Protein kinase A activators did not affect the transcellular transport or the accumulation of PAH. The PTH-induced inhibition of the accumulation of PAH was blocked by a protein kinase C inhibitor staurosporine. These results suggest that PTH inhibits the PAH transport in OK cells and that the messenger system mediated by protein kinase C, not protein kinase A, plays an important role in the regulation of PAH transport by PTH.

Regulation of p-aminohippurate transport by protein kinase C in OK kidney epithelial cells

1996 ◽  
Vol 271 (2) ◽  
pp. F469-F475 ◽  
Author(s):  
M. Takano ◽  
J. Nagai ◽  
M. Yasuhara ◽  
K. Inui
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phorbol Ester ◽  
Phorbol Esters ◽  
Basolateral Membrane ◽  
Significant Inhibition ◽  
Regulatory Control ◽  
Ok Cells ◽  
Kinase C ◽  
Apical Side

We studied the effect of phorbol 12-myristate 13-acetate (PMA), a phorbol ester which activates protein kinase C, on p-aminohippurate (PAH) transport in OK cells. PMA (10(-7) M) almost completely inhibited the transcellular transport of PAH across OK cell monolayers from the basal to the apical side, as well as the accumulation of PAH in the cells. The uptake of PAH across the basolateral membrane of OK cells was inhibited by PMA in a time-and dose-dependent fashion. Exposing the cells with other protein kinase C activators such as active phorbol esters and diacylglycerols also resulted in a significant inhibition of basolateral PAH uptake, but the inactive phorbol ester, 4 alpha-phorbol 12,13-didecanoate, had no effect. The inhibition of basolateral PAH uptake by PMA was blocked by staurosporine, an inhibitor of protein kinase C. Cycloheximide, actinomycin D, colchicine, and cytochalasin D did not affect the inhibitory effect of PMA on basolateral PAH uptake. These results suggested that the PAH transport system in OK cells is under the regulatory control of protein kinase C.

Na+/H+ Exchanger-Regulatory Factor 1 Mediates Inhibition of Phosphate Transport by Parathyroid Hormone and Second Messengers by Acting at Multiple Sites in Opossum Kidney Cells

2003 ◽  
Vol 17 (11) ◽  
pp. 2355-2364 ◽  
Author(s):  
Matthew J. Mahon ◽  
Judith A. Cole ◽  
Eleanor D. Lederer ◽  
Gino V. Segre
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Adenylyl Cyclase ◽  
Sodium Phosphate ◽  
Regulatory Factor ◽  
Opossum Kidney ◽  
Ok Cells ◽  
Kinase C ◽  
Phosphate Cotransport ◽  
Sodium Phosphate Cotransport

Abstract The opossum kidney (OK) line displays PTH-mediated activation of adenylyl cyclase and phospholipase C and inhibition of phosphate (Pi) uptake via regulation of the type IIa sodium-phosphate cotransporter, consistent with effects in vivo. OKH cells, a subclone of the OK cell line, robustly activates PTH-mediated activation of adenylyl cyclase, but is defective in PTH-mediated inhibition of sodium-phosphate cotransport and signaling via phospholipase C. Compared with wild-type OK cells, OKH cells express low levels of the Na+/H+ exchanger regulatory factor 1 (NHERF-1). Stable expression of NHERF-1 in OKH cells (OKH-N1) rescues the PTH-mediated inhibition of sodium-phosphate cotransport. NHERF-1 also restores the capacity of 8-bromo-cAMP and forskolin to inhibit Pi uptake, but the PTH dose-response for cAMP accumulation and inhibition of Pi uptake differ by 2 orders of magnitude. NHERF-1, in addition, modestly restores phorbol ester-mediated inhibition of Pi uptake, which is much weaker than that elicited by PTH. A poor correlation exists between the inhibition of Pi uptake mediated by PTH (∼60%) and the inhibition mediated by phorbol 12-myristate 13-acetate (∼30%) and the ability of these molecules to activate the protein kinase C-responsive reporter gene. Furthermore, we show that NHERF-1 directly interacts with type IIa cotransporter in OK cells. Although, PTH-mediated inhibition of Pi uptake in OK cells is largely NHERF-1 dependent, the signaling pathway(s) by which this occurs is still unclear. These pathways may involve cooperativity between cAMP- and protein kinase C-dependent pathways or activation/inhibition of an unrecognized NHERF-1-dependent pathway(s).

Protein kinase C activating phorbolesters enhance the cyclic AMP response to parathyroid hormone, forskolin and choleratoxin in mouse calvarial bones and rat osteosarcoma cells

1991 ◽  
Vol 11 (4) ◽  
pp. 203-211 ◽  
Author(s):  
Maria Ransjö
Keyword(s):  
Protein Kinase C ◽  
Parathyroid Hormone ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Phorbol Esters ◽  
Osteosarcoma Cells ◽  
Kinase C ◽  
Cyclic Amp Accumulation ◽  
Umr 106

The protein kinase C-(PKC) activating phorbol esters 12-O-tetradecanoylphorbol-13-acetate (TPA; 100 nmol/l) and phorbol 12, 13-dibutyrate (PDBU; 100 nmol/l) enhanced basal cyclin AMP accumulation in cultured neonatal mouse calvaria. The cyclic AMP response to parathyroid hormone (PTH; 10 nmol/l) and the adenylate cyclase activators forskolin (1–3 μmol/l) and choleratoxin (0.1 μmg/ml) was potentiated in a more than additive manner by TPA and PDBU. In contrast, phorbol 13-monoacetate (phorb-13; 100 nmol/l), a related compound but inactive on PKC, had no effect on basal or stimulated cyclic AMP accumulation. In the presence of indomethacin (1μmol/l), TPA and PDBU had no effect on cyclic AMP accumulation in calvarial bones per se, but were still able to cause a significant enhancement of the response to PTH, forskolin and choleratoxin. PTH-, forskolin- and choleratoxin-stimulated cyclic AMP accumulation in rat osteosarcoma cells UMR 106-01 was synergistically potentiated by TPA and PDBU, but not by phorb.-13. These data indicate that PKC enhances cyclic AMP formation and that the level of interaction may be at, or distal to, adenylate cyclase.

Effect of U-73,122, an inhibitor of phospholipase C, on actions of parathyroid hormone in opossum kidney cells

1994 ◽  
Vol 266 (2) ◽  
pp. F254-F258 ◽  
Author(s):  
K. J. Martin ◽  
C. L. McConkey ◽  
A. K. Jacob ◽  
E. A. Gonzalez ◽  
M. Khan ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Protein Kinase ◽  
Phospholipase C ◽  
Second Messengers ◽  
Cytosolic Calcium ◽  
Phosphate Transport ◽  
Response Curves ◽  
Opossum Kidney ◽  
Ok Cells ◽  
Opossum Kidney Cells

The relative roles of the adenylate cyclase-protein kinase A system (AC-PKA), the phospholipase C-protein kinase C system (PLC-PKC), and increases in cytosolic calcium in mediating the final actions of parathyroid hormone (PTH) remain ill defined. Although an important role for the PLC-PKC system in the regulation of phosphate transport in response to PTH has been suggested, previous studies from our laboratory and others, in OK cells, have emphasized the major role of AC-PKA. The present studies were designed to dissociate the second messengers for PTH by using an inhibitor of PLC (U-73,122). Studies were performed in confluent cultures of OK cells with and without preincubation with U-73,122 (1 microM). This inhibitor did not alter adenosine 3',5'-cyclic monophosphate (cAMP) production or the activation of PKA in response to PTH. Preincubation with U-73,122, however, totally abolished PTH-stimulated increases in diglyceride mass, consistent with inhibition of PLC. Activation of particulate PKC was then examined in response to PTH in the absence and presence of U-73,122. Although PTH resulted in an increase in particulate PKC activity in control cultures, this effect was abolished in the presence of U-73,122 and actually decreased significantly. Therefore, having documented marked attenuation of PLC-PKC, we next examined the effects of PTH on phosphate transport. Basal phosphate uptake was not altered by 1 microM U-73,122. Dose-response curves of the inhibition of phosphate transport in response to PTH were identical in the presence or absence of U-73,122. Thus inhibition of PLC and PKC activities did not alter the effects of PTH on phosphate transport.(ABSTRACT TRUNCATED AT 250 WORDS)

REGULATION OF PLATELET cAMP FORMATION BY PROTEIN KINASE C

1987 ◽  
Author(s):  
Sara Hopple ◽  
Mark Bushfield ◽  
Fiona Murdoch ◽  
D Euan MacIntyre
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phorbol Esters ◽  
Platelet Reactivity ◽  
Phosphodiesterase Inhibitors ◽  
Inhibitory Effect ◽  
Camp Phosphodiesterase ◽  
Camp Content ◽  
Kinase C ◽  
Camp Formation

Exogenous synthetic 1,2-diacylglycerols (e.g. 1,2-dioctanoylglycerol, DiC8) and 4β Phorbol esters (e.g. phorbol myristate acetate, PMA) routinely are used to probe the effects of protein Kinase C (PKC) on cellular responsiveness. Such agents act either independently or synergistically with elevated [Ca2+]i to induce platelet activation, but also inhibit agonist-induced inositol lipid metabolism and Ca2+ flux. These findings led to the concept that activated PKC can function as a bi-directional regulator of platelet reactivity. Therefore, DiCg and PMA were utilized to examine the effects of activated PKC on receptor-mediated stimulation and inhibition of adenylate cyclase, as monitored by cAMP accumulation. All studies were performed using intact human platelets in a modified Tyrodes solution, and cAMP was quantified by radioimmunoassay. Pretreatment (2 min.; 37°C) of platelets with PMA (≤ 300 nM) but not DiCg (200 μM) attenuated the elevation of platelet cAMP content evoked by PGD2 300 nM) but not by PGE1 (≤300 nM), PGI2 (≤100 nM) or adenosine (≤ 100 μM).These effects of PMA were unaffected by ADP scavengers, by Flurbiprofen (10 μM) or by cAMP phosphodiesterase inhibitors (IBMX, 1 mM) but were abolished by the PKC inhibitor Staurosporine (STP, 100 nM). In contrast, DiC8 (200 μM), but not PMA ( ≤ 300 nM), reduced the inhibitory effect of adrenaline (5 μM) on PGE1 (300 nM)-induced cAMP formation. This effect of DiCg was unaltered by STP (100 nM). Selective inhibition of PGD2-induced cAMP formation by PMA most probably can be attributed to PKC catalysed phosphorylation of the DP receptor. Reduction of the inhibitory effect of adrenaline by DiC8 could occur via an action at the α2 adrenoreceptor or Ni. These differential effects of PMA and DiC8 may result from differences in their distribution or efficacy, or to heterogeneity of platelet PKC.

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