Temperature-dependent activity of kinesins is regulable

Area of Science:

• Cellular biology
• Biophysics
• Molecular motors

Background:

• Cellular transport relies on motor proteins like kinesin and dynein, whose activity is temperature-sensitive.
• The interplay between opposing motors dictates cargo transport direction and duration.
• Understanding temperature effects on motor coupling is vital for cell function across varying thermal environments.

Purpose of the Study:

• To investigate the temperature dependence of kinesin motor activity.
• To determine if breaks in Arrhenius behavior occur at biologically relevant temperatures.
• To assess the influence of chemical background on motor activity transition temperatures.

Main Methods:

• Enzymatic activity assays for kinesin-1 and kinesin-3.
• Temperature-dependent kinetic measurements.
• Analysis of Arrhenius behavior under varying chemical conditions, including TMAO.

Main Results:

• Identified distinct breaks in Arrhenius behavior for kinesin-1 (4.7°C) and kinesin-3 (10.5°C).
• Observed a significant upward shift in transition temperatures (∼6°C) upon addition of 200 mM TMAO.
• Demonstrated that Arrhenius trend breaks are common across cytoskeletal motors and tunable by chemical environment.

Conclusions:

• Cytoskeletal motor activity exhibits temperature-dependent transitions beyond typical Arrhenius kinetics.
• The chemical microenvironment plays a critical role in modulating these thermal transition points.
• Findings suggest a greater tunability of motor-cargo transport in vivo than previously understood.