WAVE/Scars in platelets.
Using specific antibodies against isoforms of WAVE (WASP [Wiskott-Aldrich syndrome protein] family Verprolin-homologous protein, also called Scar), we demonstrated that human platelets express all 3 isoforms. With the use of an in vitro pull-down technique, the src homology 3 (SH3) domain of insulin receptor substrate p53 (IRSp53) precipitated WAVE2 from platelet lysates more efficiently than did profilin I. The opposite was true for WAVE1, and neither precipitated WAVE3, suggesting that WAVE isoforms have different affinities to these ligands, while the SH3 domain of abl binds to all 3 isoforms. The 3 WAVE isoforms were distributed in the actin-rich Triton X-100-insoluble pellets following platelet aggregation induced by thrombin receptor-activating peptide. We also found that all 3 WAVE isoforms are substrates for calpain in vivo and in vitro. Although portions of these 3 isoforms were commonly distributed in the actin- and actin-related protein 2 and 3 (Arp2/3)-rich edge of the lamellipodia in spreading platelets, only WAVE2 remained in the cell fringe following detergent extraction or fixation of the cells. Finally, by mass spectrometry, we found that the proteins, which reportedly interact with WAVE/Scars, are present in platelets. These data suggest that the 3 WAVE isoforms exhibit common and distinct features and may potentially be involved in the regulation of actin cytoskeleton in platelets.
Laboratory of Environmental Biology, Department of Preventive Medicine, Hokkaido University School of Medicine, Kitaku, Sapporo, 060-8638, Japan. aoda@med.hokudai.ac.jp
Atsushi
A
Oda
Hiroaki
H
Miki
Ikuo
I
Wada
Hideki
H
Yamaguchi
Daisuke
D
Yamazaki
Shiro
S
Suetsugu
Mineba
M
Nakajima
Akira
A
Nakayama
Katsuya
K
Okawa
Hiroshi
H
Miyazaki
Kazuhiko
K
Matsuno
Hans D
HD
Ochs
Laura M
LM
Machesky
Hiroyoshi
H
Fujita
Tadaomi
T
Takenawa
D008841:Actin Cytoskeleton / Q000378:metabolism; D000818:Animals; D001792:Blood Platelets / Q000502:physiology*; D019556:COS Cells; D002154:Calpain / Q000378:metabolism; D002522:Chlorocebus aethiops; D006801:Humans; D007536:Isomerism; D008840:Microfilament Proteins / Q000235:genetics* / Q000378:metabolism*; D010974:Platelet Aggregation / Q000502:physiology; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D051300:Wiskott-Aldrich Syndrome Protein Family
D008840:Microfilament Proteins; D011506:Proteins; C114864:WASF1 protein, human; C120152:WASF2 protein, human; C120153:WASF3 protein, human; D051300:Wiskott-Aldrich Syndrome Protein Family; D002154:Calpain