Vps74p controls Golgi size in an Arf1-dependent manner

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• The oncogene GOLPH3 is known to regulate Golgi size, but its link to phosphatidylinositol 4-phosphate (PI4P) effector function and Golgi cisternal maturation remains unclear.
• The yeast homolog of GOLPH3, Vps74p, has not been previously associated with Golgi size regulation.

Purpose of the Study:

• To investigate the role of Vps74p in Golgi size regulation in budding yeast.
• To determine the relationship between Vps74p, Arf1, PI4P distribution, and Golgi cisternal maturation.

Main Methods:

• Genetic deletion of VPS74 in budding yeast.
• Overexpression of Arf1 to assess phenotypic suppression.
• Microscopy and biochemical assays to analyze Golgi structure, cisternal maturation, and PI4P localization.

Main Results:

• VPS74 deletion led to enlarged late Golgi cisternae and increased cisternal maturation frequency.
• Loss of VPS74 destabilized the Golgi PI4P gradient.
• Arf1 overexpression rescued the cisternal enlargement and maturation phenotypes of ∆vps74 cells, while ∆arf1 altered Vps74p and PI4P distribution.

Conclusions:

• Vps74p, as a downstream effector of Arf1, plays a critical role in regulating Golgi size.
• Vps74p controls Golgi size by modulating cisternal maturation frequency and maintaining PI4P distribution across Golgi compartments.