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C-terminus of the P4-ATPase ATP8A2 functions in protein folding and regulation of phospholipid flippase activity
ATP8A2 is a P4-ATPase that flips phosphatidylserine and phosphatidylethanolamine across cell membranes. This generates membrane phospholipid asymmetry, a property important in many cellular processes, including vesicle trafficking. ATP8A2 deficiency causes severe neurodegenerative diseases. We inves...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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The American Society for Cell Biology
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5341728/ https://www.ncbi.nlm.nih.gov/pubmed/27932490 http://dx.doi.org/10.1091/mbc.E16-06-0453 |
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author | Chalat, Madhavan Moleschi, Kody Molday, Robert S. |
author_facet | Chalat, Madhavan Moleschi, Kody Molday, Robert S. |
author_sort | Chalat, Madhavan |
collection | PubMed |
description | ATP8A2 is a P4-ATPase that flips phosphatidylserine and phosphatidylethanolamine across cell membranes. This generates membrane phospholipid asymmetry, a property important in many cellular processes, including vesicle trafficking. ATP8A2 deficiency causes severe neurodegenerative diseases. We investigated the role of the C-terminus of ATP8A2 in its expression, subcellular localization, interaction with its subunit CDC50A, and function as a phosphatidylserine flippase. C-terminal deletion mutants exhibited a reduced tendency to solubilize in mild detergent and exit the endoplasmic reticulum. The solubilized protein, however, assembled with CDC50A and displayed phosphatidylserine flippase activity. Deletion of the C-terminal 33 residues resulted in reduced phosphatidylserine-dependent ATPase activity, phosphatidylserine flippase activity, and neurite extension in PC12 cells. These reduced activities were reversed with 60- and 80-residue C-terminal deletions. Unlike the yeast P4-ATPase Drs2, ATP8A2 is not regulated by phosphoinositides but undergoes phosphorylation on the serine residue within a CaMKII target motif. We propose a model in which the C-terminus of ATP8A2 consists of an autoinhibitor domain upstream of the C-terminal 33 residues and an anti-autoinhibitor domain at the extreme C-terminus. The latter blocks the inhibitory activity of the autoinhibitor domain. We conclude that the C-terminus plays an important role in the efficient folding and regulation of ATP8A2. |
format | Online Article Text |
id | pubmed-5341728 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | The American Society for Cell Biology |
record_format | MEDLINE/PubMed |
spelling | pubmed-53417282017-04-16 C-terminus of the P4-ATPase ATP8A2 functions in protein folding and regulation of phospholipid flippase activity Chalat, Madhavan Moleschi, Kody Molday, Robert S. Mol Biol Cell Articles ATP8A2 is a P4-ATPase that flips phosphatidylserine and phosphatidylethanolamine across cell membranes. This generates membrane phospholipid asymmetry, a property important in many cellular processes, including vesicle trafficking. ATP8A2 deficiency causes severe neurodegenerative diseases. We investigated the role of the C-terminus of ATP8A2 in its expression, subcellular localization, interaction with its subunit CDC50A, and function as a phosphatidylserine flippase. C-terminal deletion mutants exhibited a reduced tendency to solubilize in mild detergent and exit the endoplasmic reticulum. The solubilized protein, however, assembled with CDC50A and displayed phosphatidylserine flippase activity. Deletion of the C-terminal 33 residues resulted in reduced phosphatidylserine-dependent ATPase activity, phosphatidylserine flippase activity, and neurite extension in PC12 cells. These reduced activities were reversed with 60- and 80-residue C-terminal deletions. Unlike the yeast P4-ATPase Drs2, ATP8A2 is not regulated by phosphoinositides but undergoes phosphorylation on the serine residue within a CaMKII target motif. We propose a model in which the C-terminus of ATP8A2 consists of an autoinhibitor domain upstream of the C-terminal 33 residues and an anti-autoinhibitor domain at the extreme C-terminus. The latter blocks the inhibitory activity of the autoinhibitor domain. We conclude that the C-terminus plays an important role in the efficient folding and regulation of ATP8A2. The American Society for Cell Biology 2017-02-01 /pmc/articles/PMC5341728/ /pubmed/27932490 http://dx.doi.org/10.1091/mbc.E16-06-0453 Text en © 2017 Chalat et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0). “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society for Cell Biology. |
spellingShingle | Articles Chalat, Madhavan Moleschi, Kody Molday, Robert S. C-terminus of the P4-ATPase ATP8A2 functions in protein folding and regulation of phospholipid flippase activity |
title | C-terminus of the P4-ATPase ATP8A2 functions in protein folding and regulation of phospholipid flippase activity |
title_full | C-terminus of the P4-ATPase ATP8A2 functions in protein folding and regulation of phospholipid flippase activity |
title_fullStr | C-terminus of the P4-ATPase ATP8A2 functions in protein folding and regulation of phospholipid flippase activity |
title_full_unstemmed | C-terminus of the P4-ATPase ATP8A2 functions in protein folding and regulation of phospholipid flippase activity |
title_short | C-terminus of the P4-ATPase ATP8A2 functions in protein folding and regulation of phospholipid flippase activity |
title_sort | c-terminus of the p4-atpase atp8a2 functions in protein folding and regulation of phospholipid flippase activity |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5341728/ https://www.ncbi.nlm.nih.gov/pubmed/27932490 http://dx.doi.org/10.1091/mbc.E16-06-0453 |
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