Microtubule assembly and disassembly at alkaline pH

Area of Science:

• Biochemistry
• Cell Biology

Background:

• Intracellular pH can rise above neutrality under physiological conditions.
• Limited information exists on alkaline pH effects on microtubule dynamics.

Purpose of the Study:

• To investigate microtubule assembly and disassembly at alkaline pH in vitro.
• To understand the impact of alkaline pH shifts on microtubule dynamics.

Main Methods:

• Studied bovine brain microtubule protein assembly/disassembly in vitro.
• Manipulated pH to induce assembly and disassembly.
• Measured microtubule lengths and critical concentrations.

Main Results:

• Alkaline pH induces rapid microtubule disassembly, reversible by acidification.
• Critical concentration increases significantly with pH, leading to disassembly.
• Assembly-initiating capacity decreases with alkaline pH incubation.
• Direct assembly is possible up to pH 8.3, forming stable states.

Conclusions:

• Microtubule disassembly at alkaline pH occurs via uniform shortening.
• Increasing pH accelerates microtubule disassembly rates.
• Alkaline pH enhances podophyllotoxin-induced disassembly, suggesting increased treadmilling.