alphaB-crystallin extracellularly suppresses ADP-induced granule secretion from human platelets.
alphaB-crystallin, a low-molecular-weight heat shock protein (HSP), has binding sites on platelets. However, the exact role of alphaB-crystallin is not clarified. In this study, we investigated the effect of alphaB-crystallin on platelet granule secretion. alphaB-crystallin attenuated the adenosine diphosphate (ADP)-induced phosphorylation of p44/p42 mitogen-activated protein kinase (MAPK) and p38 MAPK. The ADP-stimulated HSP27 phosphorylation was markedly reduced by alphaB-crystallin. alphaB-crystallin significantly suppressed the ADP-induced secretions of both platelet-derived growth factor (PDGF)-AB and serotonin. Therefore, our results strongly suggest that alphaB-crystallin extracellularly suppresses platelet granule secretion by inhibition of HSP27 phosphorylation via p44/p42 MAPK and p38 MAPK.
Enomoto
Yukiko
Y
Department of Neurosurgery, Gifu University Graduate School of Medicine, Gifu, Japan.
Adachi
Seiji
S
Matsushima-Nishiwaki
Rie
R
Niwa
Masayuki
M
Tokuda
Haruhiko
H
Akamatsu
Shigeru
S
Doi
Tomoaki
T
Kato
Hisaaki
H
Yoshimura
Shinichi
S
Ogura
Shinji
S
Iwama
Toru
T
Kozawa
Osamu
O
D000244:Adenosine Diphosphate / Q000378:metabolism*; D001792:Blood Platelets / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D055551:HSP27 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D022142:Secretory Vesicles / Q000378:metabolism*; D038203:alpha-Crystallin B Chain / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D055551:HSP27 Heat-Shock Proteins; D038203:alpha-Crystallin B Chain; D000244:Adenosine Diphosphate; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases