Optogenetic control of PLC-γ1 activity directs cell motility

Area of Science:

• Cell Biology
• Biochemistry
• Molecular Biology

Background:

• Phospholipase C-γ1 (PLC-γ1) signaling is crucial for mesenchymal chemotaxis.
• Basal autoinhibition of PLC-γ1 complicates studies on its specific contribution to cell motility.
• Investigating PLC-γ1 regulation requires understanding its enzymatic activity and autoinhibition mechanisms.

Purpose of the Study:

• To determine if Phospholipase C-γ1 (PLC-γ1) signaling is sufficient to bias mesenchymal cell motility.
• To investigate the regulatory logic of PLC-γ1 using cancer-associated mutations.
• To clarify the role of Tyr783 phosphorylation in PLC-γ1 activity and autoinhibition.

Main Methods:

• Utilized optogenetic control (OptoPLC-γ1) to induce light-controlled membrane recruitment of PLC-γ1 in Plcg1-null fibroblasts.
• Employed cancer-associated mutations (P867R, S345F, D1165H) to investigate PLC-γ1 regulatory logic and enzyme activity.
• Assessed substrate hydrolysis, phosphorylation levels, and cell motility responses upon OptoPLC-γ1 localization.

Main Results:

• Phosphorylated Tyr783 is a marker of dysregulated autoinhibition, not a direct proxy for PLC-γ1 activity level.
• Deregulating mutations (P867R, S345F, D1165H) in OptoPLC-γ1 led to elevated phosphorylation and substrate hydrolysis upon membrane recruitment.
• Local recruitment of OptoPLC-γ1 S345F was sufficient to activate hydrolysis, polarize cell motility, and drive migration in a lipase-dependent manner.
• The motility response was spatially dose-sensitive and only partially inhibited by blocking canonical PLC-γ1 pathways.

Conclusions:

• Local activation of Phospholipase C-γ1 (PLC-γ1) is sufficient to direct and polarize cell motility.
• Cancer-associated mutations can deregulate PLC-γ1 autoinhibition, leading to increased activity.
• Findings reframe the interpretation of PLC-γ1 regulation and its role in directing cell migration.