The GOLPH3 pathway regulates Golgi shape and function and is activated by DNA damage

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• The Golgi apparatus is crucial for protein modification and transport.
• Golgi structure and function are linked to cellular processes like secretion and response to stress.
• The protein GOLPH3 (Golgi phosphoprotein 3) is involved in Golgi organization and trafficking.

Purpose of the Study:

• To elucidate the role of the PtdIns(4)P/GOLPH3/MYO18A/F-actin pathway in Golgi morphology and function.
• To investigate how this pathway is regulated, particularly in response to cellular stress like DNA damage.
• To understand the functional consequences of perturbing this pathway on cellular processes and survival.

Main Methods:

• Biochemical assays to study protein-lipid interactions (GOLPH3 and PtdIns(4)P).
• Cellular imaging techniques to observe Golgi morphology and fragmentation.
• Analysis of protein-protein interactions (GOLPH3 and MYO18A).
• Investigating cellular responses, including trafficking and cell survival, under conditions of DNA damage.

Main Results:

• GOLPH3 binds to phosphatidylinositol 4-phosphate (PtdIns(4)P) and MYO18A, connecting the Golgi to the actin cytoskeleton.
• This pathway is essential for Golgi-to-plasma membrane vesicular trafficking and influences Golgi ribbon morphology.
• DNA damage triggers DNA-PK-mediated phosphorylation of GOLPH3, enhancing its binding to MYO18A and activating the pathway.
• Pathway activation leads to Golgi fragmentation, reduced trafficking, and increased cell survival.

Conclusions:

• The PtdIns(4)P/GOLPH3/MYO18A/F-actin pathway is a key regulator of Golgi morphology and function.
• This pathway plays a critical role in the cellular response to DNA damage, promoting cell survival.
• Understanding this pathway offers new insights into the interplay between Golgi structure, cellular trafficking, and stress response.