Epidermal growth factor stimulates translocation of the class II phosphoinositide 3-kinase PI3K-C2beta to the nucleus.

2.50
Hdl Handle:
http://hdl.handle.net/10547/227186
Title:
Epidermal growth factor stimulates translocation of the class II phosphoinositide 3-kinase PI3K-C2beta to the nucleus.
Authors:
Banfic, Hrvoje; Visnjic, Dora; Mise, Nikica; Balakrishnan, Sanjeevi; Deplano, Simona; Korchev, Yuri E.; Domin, Jan
Abstract:
Although the class II phosphoinositide 3-kinase enzymes PI3K-C2alpha and PI3K-C2beta act acutely downstream of cell surface receptors they have also been localized to nuclei in mammalian cells. As with the class I PI3K enzymes, the relationship between the pools of enzyme present in cytoplasm and nuclei remains poorly understood. In this study we test the hypothesis that PI3K-C2beta translocates to nuclei in response to growth factor stimulation. Fractionating homogenates of quiescent cells revealed that less than 5% of total PI3K-C2beta resides in nuclei. Stimulation with epidermal growth factor sequentially increased levels of this enzyme, firstly in the cytosol and secondly in the nuclei. Using detergent-treated nuclei, we showed that PI3K-C2beta co-localized with lamin A/C in the nuclear matrix. This was confirmed biochemically, and a phosphoinositide kinase assay showed a statistically significant increase in nuclear PI3K-C2beta levels and lipid kinase activity following epidermal growth factor stimulation. C-terminal deletion and point mutations of PI3K-C2beta demonstrated that epidermal growth factor-driven translocation to the nucleus is dependent on a sequence of basic amino acid residues (KxKxK) that form a nuclear localization motif within the C-terminal C2 domain. Furthermore, when this sequence was expressed as an EGFP (enhanced green fluorescent protein) fusion protein, it translocated fluorescence into nuclei with an efficiency dependent upon copy number. These data demonstrate that epidermal growth factor stimulates the appearance of PI3K-C2beta in nuclei. Further, this effect is dependent on a nuclear localization signal present within the C-terminal C2 domain, indicating its bimodal function regulating phospholipid binding and shuttling PI3K-C2beta into the nucleus.
Affiliation:
Imperial College London
Citation:
Banfic, H. et al (2009) 'Epidermal growth factor stimulates translocation of the class II phosphoinositide 3-kinase PI3K-C2beta to the nucleus' Biochem. J. 422 (1):53-60
Publisher:
Portland Press
Journal:
Biochemical journal
Issue Date:
15-Aug-2009
URI:
http://hdl.handle.net/10547/227186
DOI:
10.1042/BJ20090654
PubMed ID:
19496756
Additional Links:
http://www.biochemj.org/content/422/1/53.long
Type:
Article
Language:
en
ISSN:
1470-8728
Appears in Collections:
Cell and Cryobiology Research Group

Full metadata record

DC FieldValue Language
dc.contributor.authorBanfic, Hrvojeen_GB
dc.contributor.authorVisnjic, Doraen_GB
dc.contributor.authorMise, Nikicaen_GB
dc.contributor.authorBalakrishnan, Sanjeevien_GB
dc.contributor.authorDeplano, Simonaen_GB
dc.contributor.authorKorchev, Yuri E.en_GB
dc.contributor.authorDomin, Janen_GB
dc.date.accessioned2012-06-01T14:10:50Zen
dc.date.available2012-06-01T14:10:50Zen
dc.date.issued2009-08-15en
dc.identifier.citationBanfic, H. et al (2009) 'Epidermal growth factor stimulates translocation of the class II phosphoinositide 3-kinase PI3K-C2beta to the nucleus' Biochem. J. 422 (1):53-60en_GB
dc.identifier.issn1470-8728en
dc.identifier.pmid19496756en
dc.identifier.doi10.1042/BJ20090654en
dc.identifier.urihttp://hdl.handle.net/10547/227186en
dc.description.abstractAlthough the class II phosphoinositide 3-kinase enzymes PI3K-C2alpha and PI3K-C2beta act acutely downstream of cell surface receptors they have also been localized to nuclei in mammalian cells. As with the class I PI3K enzymes, the relationship between the pools of enzyme present in cytoplasm and nuclei remains poorly understood. In this study we test the hypothesis that PI3K-C2beta translocates to nuclei in response to growth factor stimulation. Fractionating homogenates of quiescent cells revealed that less than 5% of total PI3K-C2beta resides in nuclei. Stimulation with epidermal growth factor sequentially increased levels of this enzyme, firstly in the cytosol and secondly in the nuclei. Using detergent-treated nuclei, we showed that PI3K-C2beta co-localized with lamin A/C in the nuclear matrix. This was confirmed biochemically, and a phosphoinositide kinase assay showed a statistically significant increase in nuclear PI3K-C2beta levels and lipid kinase activity following epidermal growth factor stimulation. C-terminal deletion and point mutations of PI3K-C2beta demonstrated that epidermal growth factor-driven translocation to the nucleus is dependent on a sequence of basic amino acid residues (KxKxK) that form a nuclear localization motif within the C-terminal C2 domain. Furthermore, when this sequence was expressed as an EGFP (enhanced green fluorescent protein) fusion protein, it translocated fluorescence into nuclei with an efficiency dependent upon copy number. These data demonstrate that epidermal growth factor stimulates the appearance of PI3K-C2beta in nuclei. Further, this effect is dependent on a nuclear localization signal present within the C-terminal C2 domain, indicating its bimodal function regulating phospholipid binding and shuttling PI3K-C2beta into the nucleus.en_GB
dc.language.isoenen
dc.publisherPortland Pressen_GB
dc.relation.urlhttp://www.biochemj.org/content/422/1/53.longen
dc.rightsArchived with thanks to The Biochemical journalen_GB
dc.subject.meshAmino Acid Sequenceen
dc.subject.meshCell Lineen
dc.subject.meshCell Membraneen
dc.subject.meshCell Nucleusen
dc.subject.meshCytosolen
dc.subject.meshEpidermal Growth Factoren
dc.subject.meshGreen Fluorescent Proteinsen
dc.subject.meshHumansen
dc.subject.meshLaminsen
dc.subject.meshModels, Biologicalen
dc.subject.meshMolecular Sequence Dataen
dc.subject.meshNuclear Localization Signalsen
dc.subject.meshNuclear Matrixen
dc.subject.meshPhosphatidylinositol 3-Kinasesen
dc.subject.meshProtein Transporten
dc.titleEpidermal growth factor stimulates translocation of the class II phosphoinositide 3-kinase PI3K-C2beta to the nucleus.en
dc.typeArticleen
dc.contributor.departmentImperial College Londonen_GB
dc.identifier.journalBiochemical journalen_GB

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