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Calcium-calmodulin kinase I cooperatively regulates nucleocytoplasmic shuttling of CCTα by accessing a nuclear export signal

We identified a new calmodulin kinase I (CaMKI) substrate, cytidyltransferase (CCTα), a crucial enzyme required for maintenance of cell membranes. CCTα becomes activated with translocation from the cytoplasm to the nuclear membrane, resulting in increased membrane phospholipids. Calcium-activated CC...

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Autores principales: Agassandian, Marianna, Chen, Bill B., Pulijala, Roopa, Kaercher, Leah, Glasser, Jennifer R., Mallampalli, Rama K.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3395663/
https://www.ncbi.nlm.nih.gov/pubmed/22621903
http://dx.doi.org/10.1091/mbc.E11-10-0863
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author Agassandian, Marianna
Chen, Bill B.
Pulijala, Roopa
Kaercher, Leah
Glasser, Jennifer R.
Mallampalli, Rama K.
author_facet Agassandian, Marianna
Chen, Bill B.
Pulijala, Roopa
Kaercher, Leah
Glasser, Jennifer R.
Mallampalli, Rama K.
author_sort Agassandian, Marianna
collection PubMed
description We identified a new calmodulin kinase I (CaMKI) substrate, cytidyltransferase (CCTα), a crucial enzyme required for maintenance of cell membranes. CCTα becomes activated with translocation from the cytoplasm to the nuclear membrane, resulting in increased membrane phospholipids. Calcium-activated CCTα nuclear import is mediated by binding of its C-terminus to 14-3-3 ζ, a regulator of nuclear trafficking. Here CaMK1 phosphorylates residues within this C-terminus that signals association of CCTα with 14-3-3 ζ to initiate calcium-induced nuclear entry. CaMKI docks within the CCTα membrane-binding domain (residues 290–299), a sequence that displays similarities to a canonical nuclear export signal (NES) that also binds CRM1/exportin 1. Expression of a CFP-CCTα mutant lacking residues 290–299 in cells results in cytosolically retained enzyme. CRM1/exportin 1 was required for CCTα nuclear export, and its overexpression in cells was partially sufficient to trigger CCTα nuclear export despite calcium stimulation. An isolated CFP-290-299 peptide remained in the nucleus in the presence of leptomycin B but was able to target to the cytoplasm with farnesol. Thus CaMKI vies with CRM1/exportin 1 for access to a NES, and assembly of a CaMKI–14-3-3 ζ–CCTα complex is a key effector mechanism that drives nuclear CCTα translocation.
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spelling pubmed-33956632012-09-30 Calcium-calmodulin kinase I cooperatively regulates nucleocytoplasmic shuttling of CCTα by accessing a nuclear export signal Agassandian, Marianna Chen, Bill B. Pulijala, Roopa Kaercher, Leah Glasser, Jennifer R. Mallampalli, Rama K. Mol Biol Cell Articles We identified a new calmodulin kinase I (CaMKI) substrate, cytidyltransferase (CCTα), a crucial enzyme required for maintenance of cell membranes. CCTα becomes activated with translocation from the cytoplasm to the nuclear membrane, resulting in increased membrane phospholipids. Calcium-activated CCTα nuclear import is mediated by binding of its C-terminus to 14-3-3 ζ, a regulator of nuclear trafficking. Here CaMK1 phosphorylates residues within this C-terminus that signals association of CCTα with 14-3-3 ζ to initiate calcium-induced nuclear entry. CaMKI docks within the CCTα membrane-binding domain (residues 290–299), a sequence that displays similarities to a canonical nuclear export signal (NES) that also binds CRM1/exportin 1. Expression of a CFP-CCTα mutant lacking residues 290–299 in cells results in cytosolically retained enzyme. CRM1/exportin 1 was required for CCTα nuclear export, and its overexpression in cells was partially sufficient to trigger CCTα nuclear export despite calcium stimulation. An isolated CFP-290-299 peptide remained in the nucleus in the presence of leptomycin B but was able to target to the cytoplasm with farnesol. Thus CaMKI vies with CRM1/exportin 1 for access to a NES, and assembly of a CaMKI–14-3-3 ζ–CCTα complex is a key effector mechanism that drives nuclear CCTα translocation. The American Society for Cell Biology 2012-07-15 /pmc/articles/PMC3395663/ /pubmed/22621903 http://dx.doi.org/10.1091/mbc.E11-10-0863 Text en © 2012 Agassandian 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 of Cell BD; are registered trademarks of The American Society of Cell Biology.
spellingShingle Articles
Agassandian, Marianna
Chen, Bill B.
Pulijala, Roopa
Kaercher, Leah
Glasser, Jennifer R.
Mallampalli, Rama K.
Calcium-calmodulin kinase I cooperatively regulates nucleocytoplasmic shuttling of CCTα by accessing a nuclear export signal
title Calcium-calmodulin kinase I cooperatively regulates nucleocytoplasmic shuttling of CCTα by accessing a nuclear export signal
title_full Calcium-calmodulin kinase I cooperatively regulates nucleocytoplasmic shuttling of CCTα by accessing a nuclear export signal
title_fullStr Calcium-calmodulin kinase I cooperatively regulates nucleocytoplasmic shuttling of CCTα by accessing a nuclear export signal
title_full_unstemmed Calcium-calmodulin kinase I cooperatively regulates nucleocytoplasmic shuttling of CCTα by accessing a nuclear export signal
title_short Calcium-calmodulin kinase I cooperatively regulates nucleocytoplasmic shuttling of CCTα by accessing a nuclear export signal
title_sort calcium-calmodulin kinase i cooperatively regulates nucleocytoplasmic shuttling of cctα by accessing a nuclear export signal
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3395663/
https://www.ncbi.nlm.nih.gov/pubmed/22621903
http://dx.doi.org/10.1091/mbc.E11-10-0863
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