Phosphoinositide 3-kinase in rat liver nuclei

Pei-Jung Lu, Ao Lin Hsu, Da Sheng Wang, Hong Y. Yan, Helen L. Yin, Ching Shih Chen

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Abstract

Biochemical and immunochemical data from the present investigation reveal the existence of a p85/p110 phosphoinositide 3-kinase (PI 3-kinase) in rat liver nuclei. 32P-Labeling of membrane phosphoinositides by incubating intact nuclei with [γ-32P]ATP results in the formation of [32P]phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3], accompanied by small quantities of [32P]phosphatidylinositol 3-phosphate [PtdIns(3)P]. Studies with subnuclear fractions indicate that the PI 3- kinase is not confined to nuclear membranes. The nuclear soluble fraction also contains PI 3-kinase and an array of inositidemetabolizing enzymes, including phospholipase C (PLC), phosphoinositide phosphatase, and diacylglycerol (DAG) kinase. As a result, exposure of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] to the nuclear extract in the presence of [γ-32P]ATP generates a series of 32P-labeled D-3 phosphoinositides and phosphatidic acid (PA) in an interdependent manner. On the basis of the immunological reactivity and kinetic behavior, the nuclear PI 3-kinase is analogous, if not identical, to PI 3-kinase α, and constitutes about 5% of the total PI 3-kinase in the cell. Moreover, we test the premise that nuclear PI 3-kinase may, in part, be regulated through the control of substrate availability by PtdIns(4,5)P2-binding proteins. Effect of CapG, a nuclear actin-regulatory protein, on PI 3-kinase activity is examined in view of its unique Ca2+-dependent PtdIns(4,5)P2-binding capability. In vitro data show that the CapG-mediated inhibition of nuclear PI 3-kinase is prompted by PKC phosphorylation of CapG and elevated [Ca2+]. This CapG-dependent regulation provides a plausible link between nuclear PLC and PI 3-kinase pathways for cross-communications. Taken together, these findings provide definite data concerning the presence of an autonomous PI 3-kinase cycle in rat liver nuclei. The nuclear location of PI 3-kinase may lead to a better understanding regarding its functional role in transducing signals from the plasma membrane to the nucleus in response to diverse physiological stimuli.

Original languageEnglish
Pages (from-to)5738-5745
Number of pages8
JournalBiochemistry
Volume37
Issue number16
DOIs
Publication statusPublished - 1998 Apr 21

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1-Phosphatidylinositol 4-Kinase
Phosphatidylinositols
Liver
Rats
Phosphotransferases
Phosphatidylinositol 4,5-Diphosphate
Phosphoinositide Phospholipase C
Type C Phospholipases
Adenosine Triphosphate
Diacylglycerol Kinase
Membranes
Phosphatidic Acids
Phosphorylation
Nuclear Envelope
Phosphatidylinositol 3-Kinases
Cell membranes
Phosphoric Monoester Hydrolases
Actins
Labeling
Carrier Proteins

All Science Journal Classification (ASJC) codes

  • Biochemistry

Cite this

Lu, P-J., Hsu, A. L., Wang, D. S., Yan, H. Y., Yin, H. L., & Chen, C. S. (1998). Phosphoinositide 3-kinase in rat liver nuclei. Biochemistry, 37(16), 5738-5745. https://doi.org/10.1021/bi972551g
Lu, Pei-Jung ; Hsu, Ao Lin ; Wang, Da Sheng ; Yan, Hong Y. ; Yin, Helen L. ; Chen, Ching Shih. / Phosphoinositide 3-kinase in rat liver nuclei. In: Biochemistry. 1998 ; Vol. 37, No. 16. pp. 5738-5745.
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abstract = "Biochemical and immunochemical data from the present investigation reveal the existence of a p85/p110 phosphoinositide 3-kinase (PI 3-kinase) in rat liver nuclei. 32P-Labeling of membrane phosphoinositides by incubating intact nuclei with [γ-32P]ATP results in the formation of [32P]phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3], accompanied by small quantities of [32P]phosphatidylinositol 3-phosphate [PtdIns(3)P]. Studies with subnuclear fractions indicate that the PI 3- kinase is not confined to nuclear membranes. The nuclear soluble fraction also contains PI 3-kinase and an array of inositidemetabolizing enzymes, including phospholipase C (PLC), phosphoinositide phosphatase, and diacylglycerol (DAG) kinase. As a result, exposure of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] to the nuclear extract in the presence of [γ-32P]ATP generates a series of 32P-labeled D-3 phosphoinositides and phosphatidic acid (PA) in an interdependent manner. On the basis of the immunological reactivity and kinetic behavior, the nuclear PI 3-kinase is analogous, if not identical, to PI 3-kinase α, and constitutes about 5{\%} of the total PI 3-kinase in the cell. Moreover, we test the premise that nuclear PI 3-kinase may, in part, be regulated through the control of substrate availability by PtdIns(4,5)P2-binding proteins. Effect of CapG, a nuclear actin-regulatory protein, on PI 3-kinase activity is examined in view of its unique Ca2+-dependent PtdIns(4,5)P2-binding capability. In vitro data show that the CapG-mediated inhibition of nuclear PI 3-kinase is prompted by PKC phosphorylation of CapG and elevated [Ca2+]. This CapG-dependent regulation provides a plausible link between nuclear PLC and PI 3-kinase pathways for cross-communications. Taken together, these findings provide definite data concerning the presence of an autonomous PI 3-kinase cycle in rat liver nuclei. The nuclear location of PI 3-kinase may lead to a better understanding regarding its functional role in transducing signals from the plasma membrane to the nucleus in response to diverse physiological stimuli.",
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Lu, P-J, Hsu, AL, Wang, DS, Yan, HY, Yin, HL & Chen, CS 1998, 'Phosphoinositide 3-kinase in rat liver nuclei', Biochemistry, vol. 37, no. 16, pp. 5738-5745. https://doi.org/10.1021/bi972551g

Phosphoinositide 3-kinase in rat liver nuclei. / Lu, Pei-Jung; Hsu, Ao Lin; Wang, Da Sheng; Yan, Hong Y.; Yin, Helen L.; Chen, Ching Shih.

In: Biochemistry, Vol. 37, No. 16, 21.04.1998, p. 5738-5745.

Research output: Contribution to journalArticle

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AU - Lu, Pei-Jung

AU - Hsu, Ao Lin

AU - Wang, Da Sheng

AU - Yan, Hong Y.

AU - Yin, Helen L.

AU - Chen, Ching Shih

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N2 - Biochemical and immunochemical data from the present investigation reveal the existence of a p85/p110 phosphoinositide 3-kinase (PI 3-kinase) in rat liver nuclei. 32P-Labeling of membrane phosphoinositides by incubating intact nuclei with [γ-32P]ATP results in the formation of [32P]phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3], accompanied by small quantities of [32P]phosphatidylinositol 3-phosphate [PtdIns(3)P]. Studies with subnuclear fractions indicate that the PI 3- kinase is not confined to nuclear membranes. The nuclear soluble fraction also contains PI 3-kinase and an array of inositidemetabolizing enzymes, including phospholipase C (PLC), phosphoinositide phosphatase, and diacylglycerol (DAG) kinase. As a result, exposure of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] to the nuclear extract in the presence of [γ-32P]ATP generates a series of 32P-labeled D-3 phosphoinositides and phosphatidic acid (PA) in an interdependent manner. On the basis of the immunological reactivity and kinetic behavior, the nuclear PI 3-kinase is analogous, if not identical, to PI 3-kinase α, and constitutes about 5% of the total PI 3-kinase in the cell. Moreover, we test the premise that nuclear PI 3-kinase may, in part, be regulated through the control of substrate availability by PtdIns(4,5)P2-binding proteins. Effect of CapG, a nuclear actin-regulatory protein, on PI 3-kinase activity is examined in view of its unique Ca2+-dependent PtdIns(4,5)P2-binding capability. In vitro data show that the CapG-mediated inhibition of nuclear PI 3-kinase is prompted by PKC phosphorylation of CapG and elevated [Ca2+]. This CapG-dependent regulation provides a plausible link between nuclear PLC and PI 3-kinase pathways for cross-communications. Taken together, these findings provide definite data concerning the presence of an autonomous PI 3-kinase cycle in rat liver nuclei. The nuclear location of PI 3-kinase may lead to a better understanding regarding its functional role in transducing signals from the plasma membrane to the nucleus in response to diverse physiological stimuli.

AB - Biochemical and immunochemical data from the present investigation reveal the existence of a p85/p110 phosphoinositide 3-kinase (PI 3-kinase) in rat liver nuclei. 32P-Labeling of membrane phosphoinositides by incubating intact nuclei with [γ-32P]ATP results in the formation of [32P]phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3], accompanied by small quantities of [32P]phosphatidylinositol 3-phosphate [PtdIns(3)P]. Studies with subnuclear fractions indicate that the PI 3- kinase is not confined to nuclear membranes. The nuclear soluble fraction also contains PI 3-kinase and an array of inositidemetabolizing enzymes, including phospholipase C (PLC), phosphoinositide phosphatase, and diacylglycerol (DAG) kinase. As a result, exposure of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] to the nuclear extract in the presence of [γ-32P]ATP generates a series of 32P-labeled D-3 phosphoinositides and phosphatidic acid (PA) in an interdependent manner. On the basis of the immunological reactivity and kinetic behavior, the nuclear PI 3-kinase is analogous, if not identical, to PI 3-kinase α, and constitutes about 5% of the total PI 3-kinase in the cell. Moreover, we test the premise that nuclear PI 3-kinase may, in part, be regulated through the control of substrate availability by PtdIns(4,5)P2-binding proteins. Effect of CapG, a nuclear actin-regulatory protein, on PI 3-kinase activity is examined in view of its unique Ca2+-dependent PtdIns(4,5)P2-binding capability. In vitro data show that the CapG-mediated inhibition of nuclear PI 3-kinase is prompted by PKC phosphorylation of CapG and elevated [Ca2+]. This CapG-dependent regulation provides a plausible link between nuclear PLC and PI 3-kinase pathways for cross-communications. Taken together, these findings provide definite data concerning the presence of an autonomous PI 3-kinase cycle in rat liver nuclei. The nuclear location of PI 3-kinase may lead to a better understanding regarding its functional role in transducing signals from the plasma membrane to the nucleus in response to diverse physiological stimuli.

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Lu P-J, Hsu AL, Wang DS, Yan HY, Yin HL, Chen CS. Phosphoinositide 3-kinase in rat liver nuclei. Biochemistry. 1998 Apr 21;37(16):5738-5745. https://doi.org/10.1021/bi972551g