TY - JOUR
T1 - Identification of calponin as a novel substrate of Rho-kinase
AU - Kaneko, Takako
AU - Amano, Mutsuki
AU - Maeda, Akio
AU - Goto, Hideyuki
AU - Takahashi, Katsuhito
AU - Ito, Masaaki
AU - Kaibuchi, Kozo
N1 - Funding Information:
This work was supported by Grants-in-Aid for scientific research from the Ministry of Education, Science, Sports, and Culture of Japan, by Research for the Future Program from Japan Society for the Promotion of Science, and by a grant from Human Frontier Science Program Organization. We are grateful to Akemi Takemura and Momoko Maeda for secretarial assistance.
PY - 2000/6/24
Y1 - 2000/6/24
N2 - Calponin, an F-actin-associated protein implicated in the regulation of smooth muscle contraction, is known to be phosphorylated in vitro by protein kinase C (PKC) and Ca2+/calmodulin dependent protein kinase II (CaM kinase II). Unphosphorylated calponin binds to F-actin and inhibits the actin-activated myosin ATPase activity; these properties are lost on phosphorylation. In the present study, we found that Rho-kinase phosphorylated basic calponin stoichiometrically in vitro. We identified the sites of phosphorylation of calponin by Rho-kinase as Thr-170, Ser-175, Thr-180, Thr-184, and Thr-259, and prepared antibodies that specifically recognized calponin phosphorylated at Thr-170 and Thr-184. We showed that the phosphorylation of calponin by Rho-kinase inhibited the binding of calponin to F-actin. Taken together, these results suggest that calponin is a substrate of Rho-kinase and that Rho-kinase regulates the interaction of calponin with F-actin. (C) 2000 Academic Press.
AB - Calponin, an F-actin-associated protein implicated in the regulation of smooth muscle contraction, is known to be phosphorylated in vitro by protein kinase C (PKC) and Ca2+/calmodulin dependent protein kinase II (CaM kinase II). Unphosphorylated calponin binds to F-actin and inhibits the actin-activated myosin ATPase activity; these properties are lost on phosphorylation. In the present study, we found that Rho-kinase phosphorylated basic calponin stoichiometrically in vitro. We identified the sites of phosphorylation of calponin by Rho-kinase as Thr-170, Ser-175, Thr-180, Thr-184, and Thr-259, and prepared antibodies that specifically recognized calponin phosphorylated at Thr-170 and Thr-184. We showed that the phosphorylation of calponin by Rho-kinase inhibited the binding of calponin to F-actin. Taken together, these results suggest that calponin is a substrate of Rho-kinase and that Rho-kinase regulates the interaction of calponin with F-actin. (C) 2000 Academic Press.
UR - http://www.scopus.com/inward/record.url?scp=0034709570&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034709570&partnerID=8YFLogxK
U2 - 10.1006/bbrc.2000.2901
DO - 10.1006/bbrc.2000.2901
M3 - Article
C2 - 10873572
AN - SCOPUS:0034709570
VL - 273
SP - 110
EP - 116
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 1
ER -