|
|
|
|
|
|
|
||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
BRIEF DEFINITIVE REPORT |
CORRESPONDENCE Bernhard Nieswandt: bernhard.nieswandt{at}virchow.uni-wuerzburg.de
Platelet activation and aggregation are essential to limit posttraumatic blood loss at sites of vascular injury but also contributes to arterial thrombosis, leading to myocardial infarction and stroke. Agonist-induced elevation of [Ca2+]i is a central step in platelet activation, but the underlying mechanisms are not fully understood. A major pathway for Ca2+ entry in nonexcitable cells involves receptor-mediated release of intracellular Ca2+ stores, followed by activation of store-operated calcium (SOC) channels in the plasma membrane. Stromal interaction molecule 1 (STIM1) has been identified as the Ca2+ sensor in the endoplasmic reticulum (ER) that activates Ca2+ release–activated channels in T cells, but its role in mammalian physiology is unknown. Platelets express high levels of STIM1, but its exact function has been elusive, because these cells lack a normal ER and Ca2+ is stored in a tubular system referred to as the sarcoplasmatic reticulum. We report that mice lacking STIM1 display early postnatal lethality and growth retardation. STIM1-deficient platelets have a marked defect in agonist-induced Ca2+ responses, and impaired activation and thrombus formation under flow in vitro. Importantly, mice with STIM1-deficient platelets are significantly protected from arterial thrombosis and ischemic brain infarction but have only a mild bleeding time prolongation. These results establish STIM1 as an important mediator in the pathogenesis of ischemic cardio- and cerebrovascular events.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
Related In this Issue article
| TABLE OF CONTENTS |
|
