Tetrahymena p85 is localized to the presumptive division plane before the formation of contractile ring microfilaments. p85 binds to calmodulin in a Ca2+-dependent manner and both proteins colocalize to the division furrow. Inhibition of the binding of p85 and Ca2+/calmodulin prevents both the localization of p85 and calmodulin to the division plane and the formation of the contractile ring, suggesting that the interaction of p85 and Ca2+/calmodulin is important in the formation of the contractile ring. We investigated the mechanisms of the formation of contractile ring, and the relationship among p85, CaM, and actin using co-sedimentation assay: p85 binds to G-actin in a Ca2+/calmodulin-dependent manner, but does not bind to F-actin. Therefore, we propose that a Ca2+/calmodulin signal and its target protein p85 are cooperatively involved in the recruitment of G-actin to the division plane and the formation of the contractile ring.
|Number of pages||6|
|Journal||Biochemical and Biophysical Research Communications|
|Publication status||Published - 2002|
- Actin-binding protein
- Contractile ring
- Division plane