TORC2-Gad8-dependent myosin phosphorylation modulates regulation by calcium

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Cellular responses to environmental cues involve complex signaling networks.
• Cytoskeleton and membrane organization are critical for cell cycle progression and polarized growth.
• Myosin motors play key roles in cellular organization and dynamics.

Purpose of the Study:

• To elucidate a novel regulatory mechanism for fission yeast type one myosin (Myo1).
• To investigate the role of TORC2-signalling-dependent phosphorylation in modulating Myo1 motor activity.
• To understand how Myo1 dynamics are coupled to environmental and cell-cycle cues.

Main Methods:

• Phosphorylation site analysis of Myo1 at serine 742 (S742).
• Conformational change studies of the Myo1 neck region.
• Investigation of Myo1 interactions with calmodulin light chains.
• Analysis of cellular responses to environmental and cell-cycle cues.

Main Results:

• Phosphorylation of S742 in the Myo1 neck region alters its conformation.
• S742 phosphorylation affects Myo1 interactions with calmodulin light chains.
• This phosphorylation event links calcium and TOR signaling pathways.
• Myosin-1 dynamics are modulated to coordinate actin polymerization and membrane reorganization.

Conclusions:

• A novel regulatory mechanism for Myo1 activity, dependent on TORC2-signalling, has been identified.
• S742 phosphorylation serves as a crucial link between signaling networks and myosin-1 function.
• This mechanism is vital for coordinating cellular processes like endocytosis and polarized growth.