Entry Name Platelet activation - Ursus maritimus (polar bear)
Description Platelets play a key and beneficial role for primary hemostasis on the disruption of the integrity of vessel wall. Platelet adhesion and activation at sites of vascular wall injury is initiated by adhesion to adhesive macromolecules, such as collagen and von Willebrand factor (vWF), or by soluble platelet agonists, such as ADP, thrombin, and thromboxane A2. Different receptors are stimulated by various agonists, almost converging in increasing intracellular Ca2+ concentration that stimulate platelet shape change and granule secretion and ultimately induce the "inside-out" signaling process leading to activation of the ligand-binding function of integrin alpha IIb beta 3. Binding of alpha IIb beta 3 to its ligands, mainly fibrinogen, mediates platelet adhesion and aggregation and triggers "outside-in" signaling, resulting in platelet spreading, additional granule secretion, stabilization of platelet adhesion and aggregation, and clot retraction.
Class Organismal Systems; Immune systemBRITE hierarchy
Pathway map Other DBs Organism Ursus maritimus (polar bear) [GN:
umr ]
Gene 103658775 GNAI1; guanine nucleotide-binding protein G(i) subunit alpha-1 [KO:K04630 ]
103660496 PIK3R6; phosphoinositide 3-kinase regulatory subunit 6 [KO:K21290 ]
103660497 PIK3R5; phosphoinositide 3-kinase regulatory subunit 5 [KO:K21290 ]
103660945 COL1A1; LOW QUALITY PROTEIN: collagen alpha-1(I) chain [KO:K06236 ]
103661271 ORAI1; calcium release-activated calcium channel protein 1 [KO:K16056 ]
103662093 PLCG2; 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase gamma-2 isoform X1 [KO:K05859 ] [EC:3.1.4.11 ]
103662491 ARHGEF12; rho guanine nucleotide exchange factor 12 isoform X1 [KO:K07532 ]
103663281 GNAQ; guanine nucleotide-binding protein G(q) subunit alpha [KO:K04634 ]
103663617 PIK3R1; phosphatidylinositol 3-kinase regulatory subunit alpha isoform X3 [KO:K02649 ]
103665670 GNA13; guanine nucleotide-binding protein subunit alpha-13 [KO:K04639 ]
103666874 PIK3CD; phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit delta isoform [KO:K00922 ] [EC:2.7.1.153 ]
103670766 PIK3R3; phosphatidylinositol 3-kinase regulatory subunit gamma [KO:K02649 ]
103672015 FCER1G; high affinity immunoglobulin epsilon receptor subunit gamma [KO:K07983 ]
103673419 SNAP23; synaptosomal-associated protein 23 isoform X1 [KO:K08508 ]
103674425 PLCB1; 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase beta-1 isoform X1 [KO:K05858 ] [EC:3.1.4.11 ]
103674633 PIK3CG; phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit gamma isoform isoform X1 [KO:K21289 ] [EC:2.7.1.153 ]
103674803 GNAI2; guanine nucleotide-binding protein G(i) subunit alpha-2 [KO:K04630 ]
103675000 GNAI3; guanine nucleotide-binding protein G(i) subunit alpha-3 [KO:K04630 ]
103675162 PIK3R2; phosphatidylinositol 3-kinase regulatory subunit beta [KO:K02649 ]
103676125 PIK3CA; phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha isoform [KO:K00922 ] [EC:2.7.1.153 ]
103678592 PIK3CB; phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit beta isoform isoform X1 [KO:K00922 ] [EC:2.7.1.153 ]
103680187 ARHGEF1; rho guanine nucleotide exchange factor 1 isoform X1 [KO:K12330 ]
103680852 PPP1R12A; protein phosphatase 1 regulatory subunit 12A isoform X1 [KO:K06270 ]
Compound C01245 D-myo-Inositol 1,4,5-trisphosphate
C05981 Phosphatidylinositol-3,4,5-trisphosphate
Reference Authors Li Z, Delaney MK, O'Brien KA, Du X
Title Signaling during platelet adhesion and activation.
Journal Reference Authors Broos K, De Meyer SF, Feys HB, Vanhoorelbeke K, Deckmyn H
Title Blood platelet biochemistry.
Journal Reference Authors Jurk K, Kehrel BE
Title Platelets: physiology and biochemistry.
Journal Reference Authors Offermanns S
Title Activation of platelet function through G protein-coupled receptors.
Journal Reference Authors Varga-Szabo D, Pleines I, Nieswandt B
Title Cell adhesion mechanisms in platelets.
Journal Reference Authors Yin H, Liu J, Li Z, Berndt MC, Lowell CA, Du X
Title Src family tyrosine kinase Lyn mediates VWF/GPIb-IX-induced platelet activation via the cGMP signaling pathway.
Journal Reference Authors Bergmeier W, Stefanini L
Title Novel molecules in calcium signaling in platelets.
Journal Reference Authors Cifuni SM, Wagner DD, Bergmeier W
Title CalDAG-GEFI and protein kinase C represent alternative pathways leading to activation of integrin alphaIIbbeta3 in platelets.
Journal Reference Authors Heemskerk JW, Mattheij NJ, Cosemans JM
Title Platelet-based coagulation: different populations, different functions.
Journal Reference Authors Rivera J, Lozano ML, Navarro-Nunez L, Vicente V
Title Platelet receptors and signaling in the dynamics of thrombus formation.
Journal Reference Authors Banno A, Ginsberg MH
Title Integrin activation.
Journal Reference Authors Angiolillo DJ, Ferreiro JL
Title Platelet adenosine diphosphate P2Y12 receptor antagonism: benefits and limitations of current treatment strategies and future directions.
Journal Reference Authors Joo SJ
Title Mechanisms of Platelet Activation and Integrin alphaIIbeta3.
Journal Reference Authors Harper MT, Poole AW
Title Diverse functions of protein kinase C isoforms in platelet activation and thrombus formation.
Journal Reference Authors Fitch-Tewfik JL, Flaumenhaft R
Title Platelet granule exocytosis: a comparison with chromaffin cells.
Journal Reference Authors Boylan B, Gao C, Rathore V, Gill JC, Newman DK, Newman PJ
Title Identification of FcgammaRIIa as the ITAM-bearing receptor mediating alphaIIbbeta3 outside-in integrin signaling in human platelets.
Journal Related umr04610 Complement and coagulation cascades
KO pathway 
