The effects of hydrostatic pressure on the low-Km GTPase in brain membranes from two congeneric marine fishes

J. F. Siebenaller, Thomas F. Murray

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

To investigate, the effects of hydrostatic pressure on transmembrane signaling in cold-adapted marine fishes, we examined the high-affinity GTPase activity in two congeneric marine fishes, Sebastolobus alascanus and S. altivelis. In brain membranes there are two GTPase activities, one with a low Km and one with a high Km for GTP. The high-affinity GTPase activity, characteristic of the α subunits of the guanine nucleotide binding protein pool, was stimulated by the A1 adenosine receptor agonists N6(R-phenylisopropyl)adenosine and N6-cyclopentyladenosine, and the muscarinic cholinergic agonist carbamyl choline. Pertussis toxin-catalyzed ADP-ribosylation of the membranes for 2 h at 5°C prior to the GTPase assay decreased the basal GTPase activity 30-40% and abolished N6 (R-phenylisopropyl)adenosine stimulation of GTP hydrolysis. Basal high-affinity hydrolysis of GTP, measured at 0.3 μmol·1-1GTP, was stimulated 22% in both species by 340 atm pressure. At 340 atm pressure, the apparent Km of GTP is decreased approximately 10% in each of the species, and the Vmax values are increased 11 and 15.9% in S. alascanus and S. altivelis, respectively. The apparent volume changes associated with the decreased Km of GTP and the increased Vmax ranged from-7.0 to-9.9 ml·mol-1. Increased pressure markedly decreased the efficacy of N6 (R-phenylisopropyl) adenosine, N6-cylcopentyladenosine and carbamyl choline in stimulating GTPase activity. The effects of increased hydrostatic pressure on transmembrane signal transduction by the A1 adenosine receptor-inhibitory guanine nucleotide binding protein-adenylyl cyclase system may stem, at least in part, from pressure-increased GTP hydrolysis and the concomitant termination of inhibitory signal transduction.

Original languageEnglish
Pages (from-to)626-632
Number of pages7
JournalJournal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
Volume163
Issue number8
DOIs
StatePublished - Mar 1994
Externally publishedYes

Fingerprint

Hydrostatic Pressure
GTP Phosphohydrolases
hydrostatic pressure
guanosinetriphosphatase
Hydrostatic pressure
Guanosine Triphosphate
marine fish
Fish
adenosine
brain
Brain
membrane
Membranes
hydrolysis
fish
Adenosine
Pressure
Hydrolysis
Signal transduction
Guanine Nucleotides

All Science Journal Classification (ASJC) codes

  • Physiology (medical)
  • Environmental Science(all)
  • Physiology
  • Animal Science and Zoology

Cite this

@article{fcb4f7ecad7346ac86ffa85ea73465a4,
title = "The effects of hydrostatic pressure on the low-Km GTPase in brain membranes from two congeneric marine fishes",
abstract = "To investigate, the effects of hydrostatic pressure on transmembrane signaling in cold-adapted marine fishes, we examined the high-affinity GTPase activity in two congeneric marine fishes, Sebastolobus alascanus and S. altivelis. In brain membranes there are two GTPase activities, one with a low Km and one with a high Km for GTP. The high-affinity GTPase activity, characteristic of the α subunits of the guanine nucleotide binding protein pool, was stimulated by the A1 adenosine receptor agonists N6(R-phenylisopropyl)adenosine and N6-cyclopentyladenosine, and the muscarinic cholinergic agonist carbamyl choline. Pertussis toxin-catalyzed ADP-ribosylation of the membranes for 2 h at 5°C prior to the GTPase assay decreased the basal GTPase activity 30-40{\%} and abolished N6 (R-phenylisopropyl)adenosine stimulation of GTP hydrolysis. Basal high-affinity hydrolysis of GTP, measured at 0.3 μmol·1-1GTP, was stimulated 22{\%} in both species by 340 atm pressure. At 340 atm pressure, the apparent Km of GTP is decreased approximately 10{\%} in each of the species, and the Vmax values are increased 11 and 15.9{\%} in S. alascanus and S. altivelis, respectively. The apparent volume changes associated with the decreased Km of GTP and the increased Vmax ranged from-7.0 to-9.9 ml·mol-1. Increased pressure markedly decreased the efficacy of N6 (R-phenylisopropyl) adenosine, N6-cylcopentyladenosine and carbamyl choline in stimulating GTPase activity. The effects of increased hydrostatic pressure on transmembrane signal transduction by the A1 adenosine receptor-inhibitory guanine nucleotide binding protein-adenylyl cyclase system may stem, at least in part, from pressure-increased GTP hydrolysis and the concomitant termination of inhibitory signal transduction.",
author = "Siebenaller, {J. F.} and Murray, {Thomas F.}",
year = "1994",
month = "3",
doi = "10.1007/BF00369512",
language = "English",
volume = "163",
pages = "626--632",
journal = "Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology",
issn = "0174-1578",
publisher = "Springer Verlag",
number = "8",

}

TY - JOUR

T1 - The effects of hydrostatic pressure on the low-Km GTPase in brain membranes from two congeneric marine fishes

AU - Siebenaller, J. F.

AU - Murray, Thomas F.

PY - 1994/3

Y1 - 1994/3

N2 - To investigate, the effects of hydrostatic pressure on transmembrane signaling in cold-adapted marine fishes, we examined the high-affinity GTPase activity in two congeneric marine fishes, Sebastolobus alascanus and S. altivelis. In brain membranes there are two GTPase activities, one with a low Km and one with a high Km for GTP. The high-affinity GTPase activity, characteristic of the α subunits of the guanine nucleotide binding protein pool, was stimulated by the A1 adenosine receptor agonists N6(R-phenylisopropyl)adenosine and N6-cyclopentyladenosine, and the muscarinic cholinergic agonist carbamyl choline. Pertussis toxin-catalyzed ADP-ribosylation of the membranes for 2 h at 5°C prior to the GTPase assay decreased the basal GTPase activity 30-40% and abolished N6 (R-phenylisopropyl)adenosine stimulation of GTP hydrolysis. Basal high-affinity hydrolysis of GTP, measured at 0.3 μmol·1-1GTP, was stimulated 22% in both species by 340 atm pressure. At 340 atm pressure, the apparent Km of GTP is decreased approximately 10% in each of the species, and the Vmax values are increased 11 and 15.9% in S. alascanus and S. altivelis, respectively. The apparent volume changes associated with the decreased Km of GTP and the increased Vmax ranged from-7.0 to-9.9 ml·mol-1. Increased pressure markedly decreased the efficacy of N6 (R-phenylisopropyl) adenosine, N6-cylcopentyladenosine and carbamyl choline in stimulating GTPase activity. The effects of increased hydrostatic pressure on transmembrane signal transduction by the A1 adenosine receptor-inhibitory guanine nucleotide binding protein-adenylyl cyclase system may stem, at least in part, from pressure-increased GTP hydrolysis and the concomitant termination of inhibitory signal transduction.

AB - To investigate, the effects of hydrostatic pressure on transmembrane signaling in cold-adapted marine fishes, we examined the high-affinity GTPase activity in two congeneric marine fishes, Sebastolobus alascanus and S. altivelis. In brain membranes there are two GTPase activities, one with a low Km and one with a high Km for GTP. The high-affinity GTPase activity, characteristic of the α subunits of the guanine nucleotide binding protein pool, was stimulated by the A1 adenosine receptor agonists N6(R-phenylisopropyl)adenosine and N6-cyclopentyladenosine, and the muscarinic cholinergic agonist carbamyl choline. Pertussis toxin-catalyzed ADP-ribosylation of the membranes for 2 h at 5°C prior to the GTPase assay decreased the basal GTPase activity 30-40% and abolished N6 (R-phenylisopropyl)adenosine stimulation of GTP hydrolysis. Basal high-affinity hydrolysis of GTP, measured at 0.3 μmol·1-1GTP, was stimulated 22% in both species by 340 atm pressure. At 340 atm pressure, the apparent Km of GTP is decreased approximately 10% in each of the species, and the Vmax values are increased 11 and 15.9% in S. alascanus and S. altivelis, respectively. The apparent volume changes associated with the decreased Km of GTP and the increased Vmax ranged from-7.0 to-9.9 ml·mol-1. Increased pressure markedly decreased the efficacy of N6 (R-phenylisopropyl) adenosine, N6-cylcopentyladenosine and carbamyl choline in stimulating GTPase activity. The effects of increased hydrostatic pressure on transmembrane signal transduction by the A1 adenosine receptor-inhibitory guanine nucleotide binding protein-adenylyl cyclase system may stem, at least in part, from pressure-increased GTP hydrolysis and the concomitant termination of inhibitory signal transduction.

UR - http://www.scopus.com/inward/record.url?scp=0028155041&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0028155041&partnerID=8YFLogxK

U2 - 10.1007/BF00369512

DO - 10.1007/BF00369512

M3 - Article

VL - 163

SP - 626

EP - 632

JO - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology

JF - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology

SN - 0174-1578

IS - 8

ER -