Physiological adaptation of an Antarctic Na+/K+-ATPase to the cold
Because enzymatic activity is strongly suppressed by the cold, polar poikilotherms face significant adaptive challenges. For example, at 0°C the catalytic activity of a typical enzyme from a temperate organism is reduced by more than 90%. Enzymes embedded in the plasma membrane, such as the Na+/K+-A...
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ftpubmed:oai:pubmedcentral.nih.gov:3110501 2023-05-15T13:35:52+02:00 Physiological adaptation of an Antarctic Na+/K+-ATPase to the cold Galarza-Muñoz, Gaddiel Soto-Morales, Sonia I. Holmgren, Miguel Rosenthal, Joshua J. C. 2011-07-01 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3110501 http://www.ncbi.nlm.nih.gov/pubmed/21653810 https://doi.org/10.1242/jeb.048744 en eng Company of Biologists http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3110501 http://www.ncbi.nlm.nih.gov/pubmed/21653810 http://dx.doi.org/10.1242/jeb.048744 © 2011. Research Articles Text 2011 ftpubmed https://doi.org/10.1242/jeb.048744 2013-09-03T15:41:12Z Because enzymatic activity is strongly suppressed by the cold, polar poikilotherms face significant adaptive challenges. For example, at 0°C the catalytic activity of a typical enzyme from a temperate organism is reduced by more than 90%. Enzymes embedded in the plasma membrane, such as the Na+/K+-ATPase, may be even more susceptible to the cold because of thermal effects on the lipid bilayer. Accordingly, adaptive changes in response to the cold may include adjustments to the enzyme or the surrounding lipid environment, or synergistic changes to both. To assess the contribution of the enzyme itself, we cloned orthologous Na+/K+-ATPase α-subunits from an Antarctic (Pareledone sp.; –1.8°C) and a temperate octopus (Octopus bimaculatus; ∼18°C), and compared their turnover rates and temperature sensitivities in a heterologous expression system. The primary sequences of the two pumps were found to be highly similar (97% identity), with most differences being conservative changes involving hydrophobic residues. The physiology of the pumps was studied using an electrophysiological approach in intact Xenopus oocytes. The voltage dependence of the pumps was equivalent. However, at room temperature the maximum turnover rate of the Antarctic pump was found to be 25% higher than that of the temperate pump. In addition, the Antarctic pump exhibited a lower temperature sensitivity, leading to significantly higher relative activity at lower temperatures. Orthologous Na+/K+ pumps were then isolated from two tropical and two Arctic octopus. The temperature sensitivities of these pumps closely matched those of the temperate and Antarctic pumps, respectively. Thus, reduced thermal sensitivity appears to be a common mechanism driving cold adaptation in the Na+/K+-ATPase. Text Antarc* Antarctic Arctic PubMed Central (PMC) Antarctic Arctic The Antarctic Journal of Experimental Biology 214 13 2164 2174 |
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Research Articles |
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Research Articles Galarza-Muñoz, Gaddiel Soto-Morales, Sonia I. Holmgren, Miguel Rosenthal, Joshua J. C. Physiological adaptation of an Antarctic Na+/K+-ATPase to the cold |
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Research Articles |
description |
Because enzymatic activity is strongly suppressed by the cold, polar poikilotherms face significant adaptive challenges. For example, at 0°C the catalytic activity of a typical enzyme from a temperate organism is reduced by more than 90%. Enzymes embedded in the plasma membrane, such as the Na+/K+-ATPase, may be even more susceptible to the cold because of thermal effects on the lipid bilayer. Accordingly, adaptive changes in response to the cold may include adjustments to the enzyme or the surrounding lipid environment, or synergistic changes to both. To assess the contribution of the enzyme itself, we cloned orthologous Na+/K+-ATPase α-subunits from an Antarctic (Pareledone sp.; –1.8°C) and a temperate octopus (Octopus bimaculatus; ∼18°C), and compared their turnover rates and temperature sensitivities in a heterologous expression system. The primary sequences of the two pumps were found to be highly similar (97% identity), with most differences being conservative changes involving hydrophobic residues. The physiology of the pumps was studied using an electrophysiological approach in intact Xenopus oocytes. The voltage dependence of the pumps was equivalent. However, at room temperature the maximum turnover rate of the Antarctic pump was found to be 25% higher than that of the temperate pump. In addition, the Antarctic pump exhibited a lower temperature sensitivity, leading to significantly higher relative activity at lower temperatures. Orthologous Na+/K+ pumps were then isolated from two tropical and two Arctic octopus. The temperature sensitivities of these pumps closely matched those of the temperate and Antarctic pumps, respectively. Thus, reduced thermal sensitivity appears to be a common mechanism driving cold adaptation in the Na+/K+-ATPase. |
format |
Text |
author |
Galarza-Muñoz, Gaddiel Soto-Morales, Sonia I. Holmgren, Miguel Rosenthal, Joshua J. C. |
author_facet |
Galarza-Muñoz, Gaddiel Soto-Morales, Sonia I. Holmgren, Miguel Rosenthal, Joshua J. C. |
author_sort |
Galarza-Muñoz, Gaddiel |
title |
Physiological adaptation of an Antarctic Na+/K+-ATPase to the cold |
title_short |
Physiological adaptation of an Antarctic Na+/K+-ATPase to the cold |
title_full |
Physiological adaptation of an Antarctic Na+/K+-ATPase to the cold |
title_fullStr |
Physiological adaptation of an Antarctic Na+/K+-ATPase to the cold |
title_full_unstemmed |
Physiological adaptation of an Antarctic Na+/K+-ATPase to the cold |
title_sort |
physiological adaptation of an antarctic na+/k+-atpase to the cold |
publisher |
Company of Biologists |
publishDate |
2011 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3110501 http://www.ncbi.nlm.nih.gov/pubmed/21653810 https://doi.org/10.1242/jeb.048744 |
geographic |
Antarctic Arctic The Antarctic |
geographic_facet |
Antarctic Arctic The Antarctic |
genre |
Antarc* Antarctic Arctic |
genre_facet |
Antarc* Antarctic Arctic |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3110501 http://www.ncbi.nlm.nih.gov/pubmed/21653810 http://dx.doi.org/10.1242/jeb.048744 |
op_rights |
© 2011. |
op_doi |
https://doi.org/10.1242/jeb.048744 |
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Journal of Experimental Biology |
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214 |
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13 |
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2164 |
op_container_end_page |
2174 |
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1766071461437505536 |