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Regulating contractility of the actomyosin cytoskeleton by pH
Simone Köhler1, Kurt M Schmoller, Alvaro H Crevenna
1Lehrstuhl für Biophysik E27, Technische Universität München, Garching, Germany.
Cell Reports
|September 25, 2012
Summary
Local pH changes precisely control the contractility of actin and myosin-II networks. This pH sensitivity in cytoskeletal dynamics offers a new mechanism for regulating cellular structures.
Area of Science:
- Biophysics
- Cell Biology
- Biochemistry
Background:
- The intracellular cytoskeleton, composed of F-actin and myosin-II, is vital for cellular functions like force generation and dynamics.
- Understanding the precise regulation of cytoskeletal components is key to comprehending cellular mechanics.
Purpose of the Study:
- To investigate the role of local pH in controlling the contractility of reconstituted actin-myosin-II systems.
- To elucidate the mechanism by which pH influences the interaction between actin filaments and myosin-II motor proteins.
Main Methods:
- A bottom-up approach was employed to reconstitute active actin systems.
- The contractility of these systems was measured under varying local pH conditions.
Main Results:
- Contractility of actin-myosin-II systems is sharply controlled by local pH, with a transition occurring at a pH change of only 0.1.
- The pH-dependent intrinsic crossbridge strength of myosin-II was identified as the primary factor driving this transition.
- This pH-dependent contractility was observed across all tested crosslinked actin/myosin-II systems.
Conclusions:
- Small variations in local pH serve as a critical mechanism for regulating cytoskeletal contractility.
- The findings suggest broad implications for understanding cytoskeletal dynamics and cellular regulation.
- The study highlights the tunable nature of actin-myosin-II contractility based on crosslinking proteins and pH.
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