TY - JOUR
T1 - Interaction of calmodulin with the cytoplasmic domain of platelet glycoprotein VI
AU - Andrews, Robert K.
AU - Suzuki-Inoue, Katsue
AU - Shen, Yang
AU - Tulasne, David
AU - Watson, Stephen P.
AU - Berndt, Michael C.
PY - 2002/6/1
Y1 - 2002/6/1
N2 - The platelet collagen receptor, glycoprotein VI (GPVI), and GPIb-IX-V, which binds von Willebrand factor, initiate platelet aggregation at low or high shear stress, respectively. We recently reported that positively charged, membrane-proximal sequences within cytoplasmic domains of GPIbβ and GPV of GPIb-IX-V bind calmodulin. We now show that GPVI also binds calmodulin as follows - (1) calmodulin coimmunoprecipitated with GPVI from resting platelet lysates using an anti-GPVI IgG, but partially dissociated in platelets activated by collagen or collagen-related peptide; (2) calmodulin coprecipitated from platelet lysates with maltose-binding protein (MBP) - GPVI cytoplasmic domain fusion protein, but not MBP alone; (3) GPVI-related synthetic peptide based on the membrane-proximal sequence, His269-Pro287, induced a shift in calmodulin migration on nondenaturing gels, an assay that identifies calmodulin-binding peptides. His269-Pro287 is analogous to the calmodulin-binding sequence in GPIbβ. The novel interaction of GPVI and calmodulin may regulate aspects of GPVI function.
AB - The platelet collagen receptor, glycoprotein VI (GPVI), and GPIb-IX-V, which binds von Willebrand factor, initiate platelet aggregation at low or high shear stress, respectively. We recently reported that positively charged, membrane-proximal sequences within cytoplasmic domains of GPIbβ and GPV of GPIb-IX-V bind calmodulin. We now show that GPVI also binds calmodulin as follows - (1) calmodulin coimmunoprecipitated with GPVI from resting platelet lysates using an anti-GPVI IgG, but partially dissociated in platelets activated by collagen or collagen-related peptide; (2) calmodulin coprecipitated from platelet lysates with maltose-binding protein (MBP) - GPVI cytoplasmic domain fusion protein, but not MBP alone; (3) GPVI-related synthetic peptide based on the membrane-proximal sequence, His269-Pro287, induced a shift in calmodulin migration on nondenaturing gels, an assay that identifies calmodulin-binding peptides. His269-Pro287 is analogous to the calmodulin-binding sequence in GPIbβ. The novel interaction of GPVI and calmodulin may regulate aspects of GPVI function.
UR - http://www.scopus.com/inward/record.url?scp=0036624848&partnerID=8YFLogxK
U2 - 10.1182/blood-2001-11-0008
DO - 10.1182/blood-2001-11-0008
M3 - Article
C2 - 12010829
VL - 99
SP - 4219
EP - 4221
JO - Blood
JF - Blood
SN - 0006-4971
IS - 11
ER -