Dual regulation of Glycogen Synthase Kinase 3 (GSK3)alpha/beta by Protein Kinase C (PKC)alpha and Akt promotes Thrombin-mediated Integrin alpha(IIb)beta(3) activation and granule secretion in platelets

Samantha F. Moore, Marion T. J. van den Bosch, Roger W. Hunter, Kei Sakamoto, Alastair W. Poole, Ingeborg Hers

    Research output: Contribution to journalArticle

    60 Citations (Scopus)

    Abstract

    Glycogen synthase kinase-3 is a Ser/Thr kinase, tonically active in resting cells but inhibited by phosphorylation of an N-terminal Ser residue (Ser(21) in GSK3 alpha and Ser(9) in GSK3 beta) in response to varied external stimuli. Recent work suggests that GSK3 functions as a negative regulator of platelet function, but how GSK3 is regulated in platelets has not been examined in detail. Here, we show that early thrombin-mediated GSK3 phosphorylation (0-30 s) was blocked by PKC inhibitors and largely absent in platelets from PKC alpha knock-out mice. In contrast, late (2-5 min) GSK3 phosphorylation was dependent on the PI3K/Akt pathway. Similarly, early thrombin-mediated inhibition of GSK3 activity was blocked in PKC alpha knock-out platelets, whereas the Akt inhibitor MK2206 reduced late thrombin-mediated GSK3 inhibition and largely prevented GSK3 inhibition in PKC alpha knock-out platelets. More importantly, GSK3 phosphorylation contributes to platelet function as knock-in mice where GSK3 alpha Ser(21) and GSK3 beta Ser(9) were mutated to Ala showed a significant reduction in PAR4-mediated platelet aggregation, fibrinogen binding, and P-selectin expression, whereas the GSK3 inhibitor CHIR99021 enhanced these responses. Together, these results demonstrate that PKC alpha and Akt modulate platelet function by phosphorylating and inhibiting GSK3 alpha/beta, thereby relieving the negative effect of GSK3 alpha/beta on thrombin-mediated platelet activation.

    Original languageEnglish
    Pages (from-to)3918-3928
    Number of pages11
    JournalJournal of Biological Chemistry
    Volume288
    Issue number6
    DOIs
    Publication statusPublished - 2013

    Keywords

    • INSULIN
    • INHIBITORS
    • COLLAGEN
    • MICE
    • AGGREGATION
    • PHOSPHORYLATION
    • PHOSPHOINOSITIDE 3-KINASE
    • G(I) SIGNALING PATHWAYS

    Cite this

    Moore, Samantha F. ; van den Bosch, Marion T. J. ; Hunter, Roger W. ; Sakamoto, Kei ; Poole, Alastair W. ; Hers, Ingeborg. / Dual regulation of Glycogen Synthase Kinase 3 (GSK3)alpha/beta by Protein Kinase C (PKC)alpha and Akt promotes Thrombin-mediated Integrin alpha(IIb)beta(3) activation and granule secretion in platelets. In: Journal of Biological Chemistry. 2013 ; Vol. 288, No. 6. pp. 3918-3928.
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    abstract = "Glycogen synthase kinase-3 is a Ser/Thr kinase, tonically active in resting cells but inhibited by phosphorylation of an N-terminal Ser residue (Ser(21) in GSK3 alpha and Ser(9) in GSK3 beta) in response to varied external stimuli. Recent work suggests that GSK3 functions as a negative regulator of platelet function, but how GSK3 is regulated in platelets has not been examined in detail. Here, we show that early thrombin-mediated GSK3 phosphorylation (0-30 s) was blocked by PKC inhibitors and largely absent in platelets from PKC alpha knock-out mice. In contrast, late (2-5 min) GSK3 phosphorylation was dependent on the PI3K/Akt pathway. Similarly, early thrombin-mediated inhibition of GSK3 activity was blocked in PKC alpha knock-out platelets, whereas the Akt inhibitor MK2206 reduced late thrombin-mediated GSK3 inhibition and largely prevented GSK3 inhibition in PKC alpha knock-out platelets. More importantly, GSK3 phosphorylation contributes to platelet function as knock-in mice where GSK3 alpha Ser(21) and GSK3 beta Ser(9) were mutated to Ala showed a significant reduction in PAR4-mediated platelet aggregation, fibrinogen binding, and P-selectin expression, whereas the GSK3 inhibitor CHIR99021 enhanced these responses. Together, these results demonstrate that PKC alpha and Akt modulate platelet function by phosphorylating and inhibiting GSK3 alpha/beta, thereby relieving the negative effect of GSK3 alpha/beta on thrombin-mediated platelet activation.",
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    Dual regulation of Glycogen Synthase Kinase 3 (GSK3)alpha/beta by Protein Kinase C (PKC)alpha and Akt promotes Thrombin-mediated Integrin alpha(IIb)beta(3) activation and granule secretion in platelets. / Moore, Samantha F.; van den Bosch, Marion T. J.; Hunter, Roger W.; Sakamoto, Kei; Poole, Alastair W.; Hers, Ingeborg.

    In: Journal of Biological Chemistry, Vol. 288, No. 6, 2013, p. 3918-3928.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Dual regulation of Glycogen Synthase Kinase 3 (GSK3)alpha/beta by Protein Kinase C (PKC)alpha and Akt promotes Thrombin-mediated Integrin alpha(IIb)beta(3) activation and granule secretion in platelets

    AU - Moore, Samantha F.

    AU - van den Bosch, Marion T. J.

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    AU - Sakamoto, Kei

    AU - Poole, Alastair W.

    AU - Hers, Ingeborg

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    AB - Glycogen synthase kinase-3 is a Ser/Thr kinase, tonically active in resting cells but inhibited by phosphorylation of an N-terminal Ser residue (Ser(21) in GSK3 alpha and Ser(9) in GSK3 beta) in response to varied external stimuli. Recent work suggests that GSK3 functions as a negative regulator of platelet function, but how GSK3 is regulated in platelets has not been examined in detail. Here, we show that early thrombin-mediated GSK3 phosphorylation (0-30 s) was blocked by PKC inhibitors and largely absent in platelets from PKC alpha knock-out mice. In contrast, late (2-5 min) GSK3 phosphorylation was dependent on the PI3K/Akt pathway. Similarly, early thrombin-mediated inhibition of GSK3 activity was blocked in PKC alpha knock-out platelets, whereas the Akt inhibitor MK2206 reduced late thrombin-mediated GSK3 inhibition and largely prevented GSK3 inhibition in PKC alpha knock-out platelets. More importantly, GSK3 phosphorylation contributes to platelet function as knock-in mice where GSK3 alpha Ser(21) and GSK3 beta Ser(9) were mutated to Ala showed a significant reduction in PAR4-mediated platelet aggregation, fibrinogen binding, and P-selectin expression, whereas the GSK3 inhibitor CHIR99021 enhanced these responses. Together, these results demonstrate that PKC alpha and Akt modulate platelet function by phosphorylating and inhibiting GSK3 alpha/beta, thereby relieving the negative effect of GSK3 alpha/beta on thrombin-mediated platelet activation.

    KW - INSULIN

    KW - INHIBITORS

    KW - COLLAGEN

    KW - MICE

    KW - AGGREGATION

    KW - PHOSPHORYLATION

    KW - PHOSPHOINOSITIDE 3-KINASE

    KW - G(I) SIGNALING PATHWAYS

    U2 - 10.1074/jbc.M112.429936

    DO - 10.1074/jbc.M112.429936

    M3 - Article

    VL - 288

    SP - 3918

    EP - 3928

    JO - Journal of Biological Chemistry

    JF - Journal of Biological Chemistry

    SN - 0021-9258

    IS - 6

    ER -