Platelet Activation Granule Release

Activated platelets rapidly release the contents of three distinct types of preformed intracellular vesicles. Dense granules contain phosphates, purines, and bioactive amines. Lysosomes contain glycosidases and acid proteases. Proteins from alpha granule membranes localize to the platelet surface upon granule release and contribute to platelet adhesion and activation. Alpha granules contain a large number of soluble mediators that promote inflammation, both positively and negatively regulate the coagulation cascade, and promote wound healing to help resolve tissue damage.

Please view our related interactive pathways covering additional aspects of platelet activation:

Dense Granules
ADPMagnesium
ATPPolyphosphates
CalciumPyrophosphate
EpinephrineSerotonin
HistamineSTIM1, 2 (NovusBio.com)
Lysosomes
alpha-Galactosidase/a-GalEndo-beta-N-acetylglucosaminidase H/Endo H
alpha-L-FucosidaseENGASE/beta-N-Acetylglucosaminidase (NovusBio.com)
ASAHL/N-acylethanolamine-hydrolyzing Acid AmidaseGlucosylceramidase/GBA
beta-Defensin 2, 3Heparinase/HPSE
beta-Galactosidase-1/GLB1Hexosaminidase A, B
beta-Glucuronidase/GUSBHyaluronidase-2/HYAL2 (NovusBio.com)
CAMP/LL37/FALL39Lactate Dehydrogenase A, B
CatalaseLMW-PTP/ACP1
Cathepsin A/Lysosomal Carboxypeptidase AMAN2B1 (NovusBio.com)
Endo-beta-N-acetylglucosaminidase F1/Endo F1NEU-1/Sialidase-1
Endo-beta-N-acetylglucosaminidase F3/Endo F3Neuramidase-3 (NovusBio.com)
 STIM1, 2 (NovusBio.com)
Alpha Granule Soluble Factors
ThrombosisInflammationWound Healing
AngiostatinADAMDEC1 (NovusBio.com)Angiopoietin-1
APLP-2APRIL/TNFSF13EGF
Coagulation Factor II/ThrombinCCL2/JE/MCP-1Endostatin
Coagulation Factor V (NovusBio.com)CCL3/MIP-1 alphaFGF basic
Coagulation Factor XICCL5/RANTESHGF
Coagulation Factor XIII (NovusBio.com)CD40 Ligand/TNFSF5IGF-I
FibrinogenComplement Component C3aLatent TGF-beta bp1
FibronectinComplement Component C4 (NovusBio.com)MMP-1, 2, 9
KininogenComplement Factor HPDGF Family
Laminin alpha 3/Laminin-5CXCL1/GRO alpha/KC/CINC-1Protein Disulfide Isomerase
Laminin alpha 4CXCL4/PF4SPARC
Laminin gamma 1CXCL5TGF-beta 1
Multimerin-1/EMILIN-4 (NovusBio.com)CXCL7/NAP-2Thymosin beta 4
Plasmin (NovusBio.com)CXCL8/IL-8TIMP-1, 4
PlasminogenCXCL12/SDF-1VEGF
Protease Nexin-2/Amyloid beta-A4Fas/TNFRSF6/CD95VEGF-C
Protein S/PROS1IL-1 beta/IL-1F2 
Serpin C1/Antithrombin-IIIIL-7 
Serpin E1/PAI-1PLA2G2A 
Serpin F2/alpha 2-AntiplasminP-Selectin/CD62P 
TFPISerpin G1/C1 inhibitor 
Thrombospondin-1TRAIL/TNFSF10 
VitronectinTREML1/TLT-1 
vWF-A2TWEAK/TNFSF12 
Alpha Granule Membrane Proteins
CD9Glut3SNAP23
CD31/PECAM-1Glycoprotein V/CD42dSyntaxin 4, 8, 11 (NovusBio.com)
CD36/SR-B3GPVISyntaxin-BP2/Munc18-2
CD40 Ligand/TNFSF5GPIX/CD42a (NovusBio.com)Syntaxin-BP3/Munc18c
GP1BB (NovusBio.com)Integrin alpha 2b beta 3TREML1/TLT-1
CD63Integrin alpha 6/CD49fUNC13D/Munc13-4
CD109P-Selectin/CD62PVAMP-2, 3, 7, 8 (NovusBio.com)
Epimorphin/Syntaxin 2PKHD1L1/Fibrocystin-L (NovusBio.com) 
ESAMSeptin-5/CDCrel-1 (NovusBio.com) 
Fc gamma RIIA/CD32aSiglec-7/CD328 

Upon activation, platelets rapidly release the contents of three distinct types of preformed intracellular vesicles. Dense granules contain phosphates, purines, and bioactive amines. Lysosomes contain glycosidases and acid proteases. Proteins from alpha granule membranes localize to the platelet surface upon granule release and contribute to platelet adhesion and activation. Alpha granules also contain a large number of soluble mediators that promote inflammation, both positively and negatively regulate the coagulation cascade, and promote wound healing to help resolve tissue damage.