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GTP avoidance in Tetrahymena thermophila requires tyrosine kinase activity, intracellular calcium, NOS, and guanylyl cyclase.

Bartholomew J, Reichart J, Mundy R, Recktenwald J, Keyser S, Riddle M, Kuruvilla H - Purinergic Signal. (2007)

Bottom Line: However, the intracellular mechanisms involved in GTP avoidance have not been previously documented.Similarly, pharmacological inhibitors of phospholipase C, NOS, and guanylyl cyclase all eliminated Tetrahymena avoidance to GTP.Immunofluorescence data shows evidence of tyrosine kinase activity in the cilia, suggesting that this enzyme activity could be directly involved in ciliary reversal.

View Article: PubMed Central - PubMed

Affiliation: Department of Science and Mathematics, Cedarville University, Cedarville, OH, 45314, USA.

ABSTRACT
Guanosine 5'-triphosphate (GTP) is a chemorepellent in Tetrahymena thermophila that has been shown to stimulate cell division as well as ciliary reversal. Previous studies have proposed that GTP avoidance is linked to a receptor-mediated, calcium-based depolarization. However, the intracellular mechanisms involved in GTP avoidance have not been previously documented. In this study, we examine the hypothesis that GTP signals through a tyrosine kinase pathway in T. thermophila. Using behavioral assays, enzyme immunosorbent assays, Western blotting, and immunofluorescence, we present data that implicate a tyrosine kinase, phospholipase C, intracellular calcium, nitric oxide synthase (NOS) and guanylyl cyclase in GTP signaling. The tyrosine kinase inhibitor genistein eliminates GTP avoidance in Tetrahymena in behavioral assays. Similarly, pharmacological inhibitors of phospholipase C, NOS, and guanylyl cyclase all eliminated Tetrahymena avoidance to GTP. Immunofluorescence data shows evidence of tyrosine kinase activity in the cilia, suggesting that this enzyme activity could be directly involved in ciliary reversal.

No MeSH data available.


Related in: MedlinePlus

The phospholipase C inhibitor 1-(6-(17β-3-methoxyestra-1,3,5(10)-trien-17-yl) amino)hexyl)-1H-pyrrole-2,5-dione (U73122) blocks avoidance to 100 μM guanosine-5′-O-(3-thio)triphosphate (GTP-γ-S) in Tetrahymena. Baseline avoidance was reached at a U73122 concentration of 1 μM. The inhibition constant IC50 of this compound was near 0.001 μM. Data shown is mean +/− standard deviation (SD) of three or more trials
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Fig4: The phospholipase C inhibitor 1-(6-(17β-3-methoxyestra-1,3,5(10)-trien-17-yl) amino)hexyl)-1H-pyrrole-2,5-dione (U73122) blocks avoidance to 100 μM guanosine-5′-O-(3-thio)triphosphate (GTP-γ-S) in Tetrahymena. Baseline avoidance was reached at a U73122 concentration of 1 μM. The inhibition constant IC50 of this compound was near 0.001 μM. Data shown is mean +/− standard deviation (SD) of three or more trials

Mentions: The data we have compiled here are consistent with the hypothesis that the previously described GTP receptor [1] signals through a tyrosine kinase (Fig. 2, 3). The GTP signaling pathway also involves phospholipase C (Fig. 4), intracellular calcium (Fig. 5), NOS (Fig. 6), and guanylyl cyclase (Fig. 7). The proposed GTP signaling pathway is outlined in Fig. 8.Fig. 4


GTP avoidance in Tetrahymena thermophila requires tyrosine kinase activity, intracellular calcium, NOS, and guanylyl cyclase.

Bartholomew J, Reichart J, Mundy R, Recktenwald J, Keyser S, Riddle M, Kuruvilla H - Purinergic Signal. (2007)

The phospholipase C inhibitor 1-(6-(17β-3-methoxyestra-1,3,5(10)-trien-17-yl) amino)hexyl)-1H-pyrrole-2,5-dione (U73122) blocks avoidance to 100 μM guanosine-5′-O-(3-thio)triphosphate (GTP-γ-S) in Tetrahymena. Baseline avoidance was reached at a U73122 concentration of 1 μM. The inhibition constant IC50 of this compound was near 0.001 μM. Data shown is mean +/− standard deviation (SD) of three or more trials
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2377316&req=5

Fig4: The phospholipase C inhibitor 1-(6-(17β-3-methoxyestra-1,3,5(10)-trien-17-yl) amino)hexyl)-1H-pyrrole-2,5-dione (U73122) blocks avoidance to 100 μM guanosine-5′-O-(3-thio)triphosphate (GTP-γ-S) in Tetrahymena. Baseline avoidance was reached at a U73122 concentration of 1 μM. The inhibition constant IC50 of this compound was near 0.001 μM. Data shown is mean +/− standard deviation (SD) of three or more trials
Mentions: The data we have compiled here are consistent with the hypothesis that the previously described GTP receptor [1] signals through a tyrosine kinase (Fig. 2, 3). The GTP signaling pathway also involves phospholipase C (Fig. 4), intracellular calcium (Fig. 5), NOS (Fig. 6), and guanylyl cyclase (Fig. 7). The proposed GTP signaling pathway is outlined in Fig. 8.Fig. 4

Bottom Line: However, the intracellular mechanisms involved in GTP avoidance have not been previously documented.Similarly, pharmacological inhibitors of phospholipase C, NOS, and guanylyl cyclase all eliminated Tetrahymena avoidance to GTP.Immunofluorescence data shows evidence of tyrosine kinase activity in the cilia, suggesting that this enzyme activity could be directly involved in ciliary reversal.

View Article: PubMed Central - PubMed

Affiliation: Department of Science and Mathematics, Cedarville University, Cedarville, OH, 45314, USA.

ABSTRACT
Guanosine 5'-triphosphate (GTP) is a chemorepellent in Tetrahymena thermophila that has been shown to stimulate cell division as well as ciliary reversal. Previous studies have proposed that GTP avoidance is linked to a receptor-mediated, calcium-based depolarization. However, the intracellular mechanisms involved in GTP avoidance have not been previously documented. In this study, we examine the hypothesis that GTP signals through a tyrosine kinase pathway in T. thermophila. Using behavioral assays, enzyme immunosorbent assays, Western blotting, and immunofluorescence, we present data that implicate a tyrosine kinase, phospholipase C, intracellular calcium, nitric oxide synthase (NOS) and guanylyl cyclase in GTP signaling. The tyrosine kinase inhibitor genistein eliminates GTP avoidance in Tetrahymena in behavioral assays. Similarly, pharmacological inhibitors of phospholipase C, NOS, and guanylyl cyclase all eliminated Tetrahymena avoidance to GTP. Immunofluorescence data shows evidence of tyrosine kinase activity in the cilia, suggesting that this enzyme activity could be directly involved in ciliary reversal.

No MeSH data available.


Related in: MedlinePlus