Abstract
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.
Original language | English |
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Pages (from-to) | 110-116 |
Number of pages | 7 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 273 |
Issue number | 1 |
DOIs | |
Publication status | Published - 24-06-2000 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Biophysics
- Biochemistry
- Molecular Biology
- Cell Biology