G(12/13) signaling pathways substitute for integrin αIIbβ3-signaling for thromboxane generation in platelets

Kamala Bhavaraju; Parth R Lakhani; Robert T Dorsam; Jianguo Jin; Ian S Hitchcock; Archana Sanjay; Satya P Kunapuli

doi:10.1371/journal.pone.0016586

G(12/13) signaling pathways substitute for integrin αIIbβ3-signaling for thromboxane generation in platelets

Kamala Bhavaraju, Parth R Lakhani, Robert T Dorsam, Jianguo Jin, Ian S Hitchcock, Archana Sanjay, Satya P Kunapuli

Biology

Research output: Contribution to journal › Article › peer-review

Abstract

BACKGROUND: We have previously shown that ADP-induced TXA(2) generation requires signaling from αIIbβ3 integrin in platelets. Here we observed that, unlike ADP, protease-activated receptor (PAR)-mediated TXA(2) generation occurs independently of αIIbβ3. PAR agonists, but not ADP, activate G(12/13) signaling pathways. Hence, we evaluated the role of these pathways in TXA(2) generation.

PRINCIPAL FINDINGS: Inhibition of ADP-induced thromboxane generation by fibrinogen receptor antagonist SC57101 was rescued by co-stimulation of G(12/13) pathways with YFLLRNP. This observation suggested an existence of a common signaling effector downstream of integrins and G(12/13) pathways. Hence, we evaluated role of three potential tyrosine kinases; c-Src, Syk and FAK (Focal Adhesion Kinase) that are known to be activated by integrins. c-Src and Syk kinase did not play a role in ADP-induced functional responses in platelets. Selective activation of G(12/13) pathways resulted in the activation of FAK, in the absence of integrin signaling. Interestingly, αIIbβ3-mediated FAK activation occurred in a Src family kinase (SFK)-independent manner whereas G(12/13) pathway caused FAK activation in a SFK and RhoA-dependent manner. A FAK selective inhibitor TAE-226, blocked TXA(2) generation. However, in comparison to WT mice, Pf4-Cre/Fak-Floxed mice did not show any difference in platelet TXA(2) generation.

CONCLUSIONS: Therefore, we conclude that differential activation of FAK occurs downstream of Integrins and G(12/13) pathways. However, the common effector molecule, possibly a tyrosine kinase downstream of integrins and G(12/13) pathways contributing to TXA(2) generation in platelets remains elusive.

Original language	English
Article number	e16586
Pages (from-to)	e16586
Journal	PLoS ONE
Volume	6
Issue number	2
DOIs	https://doi.org/10.1371/journal.pone.0016586
Publication status	Published - 2011

Keywords

Adenosine Diphosphate
Animals
Blood Platelets
Enzyme Activation
Focal Adhesion Protein-Tyrosine Kinases
GTP-Binding Protein alpha Subunits, G12-G13
Humans
Intracellular Signaling Peptides and Proteins
Mice
Platelet Glycoprotein GPIIb-IIIa Complex
Protein-Tyrosine Kinases
Proto-Oncogene Proteins pp60(c-src)
Signal Transduction
Thromboxane A2
rho-Associated Kinases

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Cite this

@article{be4e953a542143158c6ef3369320ef64,

title = "G(12/13) signaling pathways substitute for integrin αIIbβ3-signaling for thromboxane generation in platelets",

abstract = "BACKGROUND: We have previously shown that ADP-induced TXA(2) generation requires signaling from αIIbβ3 integrin in platelets. Here we observed that, unlike ADP, protease-activated receptor (PAR)-mediated TXA(2) generation occurs independently of αIIbβ3. PAR agonists, but not ADP, activate G(12/13) signaling pathways. Hence, we evaluated the role of these pathways in TXA(2) generation.PRINCIPAL FINDINGS: Inhibition of ADP-induced thromboxane generation by fibrinogen receptor antagonist SC57101 was rescued by co-stimulation of G(12/13) pathways with YFLLRNP. This observation suggested an existence of a common signaling effector downstream of integrins and G(12/13) pathways. Hence, we evaluated role of three potential tyrosine kinases; c-Src, Syk and FAK (Focal Adhesion Kinase) that are known to be activated by integrins. c-Src and Syk kinase did not play a role in ADP-induced functional responses in platelets. Selective activation of G(12/13) pathways resulted in the activation of FAK, in the absence of integrin signaling. Interestingly, αIIbβ3-mediated FAK activation occurred in a Src family kinase (SFK)-independent manner whereas G(12/13) pathway caused FAK activation in a SFK and RhoA-dependent manner. A FAK selective inhibitor TAE-226, blocked TXA(2) generation. However, in comparison to WT mice, Pf4-Cre/Fak-Floxed mice did not show any difference in platelet TXA(2) generation.CONCLUSIONS: Therefore, we conclude that differential activation of FAK occurs downstream of Integrins and G(12/13) pathways. However, the common effector molecule, possibly a tyrosine kinase downstream of integrins and G(12/13) pathways contributing to TXA(2) generation in platelets remains elusive.",

keywords = "Adenosine Diphosphate, Animals, Blood Platelets, Enzyme Activation, Focal Adhesion Protein-Tyrosine Kinases, GTP-Binding Protein alpha Subunits, G12-G13, Humans, Intracellular Signaling Peptides and Proteins, Mice, Platelet Glycoprotein GPIIb-IIIa Complex, Protein-Tyrosine Kinases, Proto-Oncogene Proteins pp60(c-src), Signal Transduction, Thromboxane A2, rho-Associated Kinases",

author = "Kamala Bhavaraju and Lakhani, {Parth R} and Dorsam, {Robert T} and Jianguo Jin and Hitchcock, {Ian S} and Archana Sanjay and Kunapuli, {Satya P}",

year = "2011",

doi = "10.1371/journal.pone.0016586",

language = "English",

volume = "6",

pages = "e16586",

journal = "PLoS ONE",

issn = "1932-6203",

publisher = "Public Library of Science",

number = "2",

}

TY - JOUR

T1 - G(12/13) signaling pathways substitute for integrin αIIbβ3-signaling for thromboxane generation in platelets

AU - Bhavaraju, Kamala

AU - Lakhani, Parth R

AU - Dorsam, Robert T

AU - Jin, Jianguo

AU - Hitchcock, Ian S

AU - Sanjay, Archana

AU - Kunapuli, Satya P

PY - 2011

Y1 - 2011

N2 - BACKGROUND: We have previously shown that ADP-induced TXA(2) generation requires signaling from αIIbβ3 integrin in platelets. Here we observed that, unlike ADP, protease-activated receptor (PAR)-mediated TXA(2) generation occurs independently of αIIbβ3. PAR agonists, but not ADP, activate G(12/13) signaling pathways. Hence, we evaluated the role of these pathways in TXA(2) generation.PRINCIPAL FINDINGS: Inhibition of ADP-induced thromboxane generation by fibrinogen receptor antagonist SC57101 was rescued by co-stimulation of G(12/13) pathways with YFLLRNP. This observation suggested an existence of a common signaling effector downstream of integrins and G(12/13) pathways. Hence, we evaluated role of three potential tyrosine kinases; c-Src, Syk and FAK (Focal Adhesion Kinase) that are known to be activated by integrins. c-Src and Syk kinase did not play a role in ADP-induced functional responses in platelets. Selective activation of G(12/13) pathways resulted in the activation of FAK, in the absence of integrin signaling. Interestingly, αIIbβ3-mediated FAK activation occurred in a Src family kinase (SFK)-independent manner whereas G(12/13) pathway caused FAK activation in a SFK and RhoA-dependent manner. A FAK selective inhibitor TAE-226, blocked TXA(2) generation. However, in comparison to WT mice, Pf4-Cre/Fak-Floxed mice did not show any difference in platelet TXA(2) generation.CONCLUSIONS: Therefore, we conclude that differential activation of FAK occurs downstream of Integrins and G(12/13) pathways. However, the common effector molecule, possibly a tyrosine kinase downstream of integrins and G(12/13) pathways contributing to TXA(2) generation in platelets remains elusive.

AB - BACKGROUND: We have previously shown that ADP-induced TXA(2) generation requires signaling from αIIbβ3 integrin in platelets. Here we observed that, unlike ADP, protease-activated receptor (PAR)-mediated TXA(2) generation occurs independently of αIIbβ3. PAR agonists, but not ADP, activate G(12/13) signaling pathways. Hence, we evaluated the role of these pathways in TXA(2) generation.PRINCIPAL FINDINGS: Inhibition of ADP-induced thromboxane generation by fibrinogen receptor antagonist SC57101 was rescued by co-stimulation of G(12/13) pathways with YFLLRNP. This observation suggested an existence of a common signaling effector downstream of integrins and G(12/13) pathways. Hence, we evaluated role of three potential tyrosine kinases; c-Src, Syk and FAK (Focal Adhesion Kinase) that are known to be activated by integrins. c-Src and Syk kinase did not play a role in ADP-induced functional responses in platelets. Selective activation of G(12/13) pathways resulted in the activation of FAK, in the absence of integrin signaling. Interestingly, αIIbβ3-mediated FAK activation occurred in a Src family kinase (SFK)-independent manner whereas G(12/13) pathway caused FAK activation in a SFK and RhoA-dependent manner. A FAK selective inhibitor TAE-226, blocked TXA(2) generation. However, in comparison to WT mice, Pf4-Cre/Fak-Floxed mice did not show any difference in platelet TXA(2) generation.CONCLUSIONS: Therefore, we conclude that differential activation of FAK occurs downstream of Integrins and G(12/13) pathways. However, the common effector molecule, possibly a tyrosine kinase downstream of integrins and G(12/13) pathways contributing to TXA(2) generation in platelets remains elusive.

KW - Adenosine Diphosphate

KW - Animals

KW - Blood Platelets

KW - Enzyme Activation

KW - Focal Adhesion Protein-Tyrosine Kinases

KW - GTP-Binding Protein alpha Subunits, G12-G13

KW - Humans

KW - Intracellular Signaling Peptides and Proteins

KW - Mice

KW - Platelet Glycoprotein GPIIb-IIIa Complex

KW - Protein-Tyrosine Kinases

KW - Proto-Oncogene Proteins pp60(c-src)

KW - Signal Transduction

KW - Thromboxane A2

KW - rho-Associated Kinases

U2 - 10.1371/journal.pone.0016586

DO - 10.1371/journal.pone.0016586

M3 - Article

C2 - 21347357

SN - 1932-6203

VL - 6

SP - e16586

JO - PLoS ONE

JF - PLoS ONE

IS - 2

M1 - e16586

ER -