The TOG protein Stu2 is regulated by acetylation

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Stu2 is a crucial microtubule-associated protein (MAP) in S. cerevisiae, belonging to the XMAP215/Dis1/CKAP5/ch-TOG family.
• Stu2 controls microtubule polymerization, depolymerization, kinetochore-chromosome linkage, and spindle pole body (SPB) assembly.
• While phosphorylation regulates Stu2 kinetochore localization, other regulatory mechanisms remain largely unknown.

Purpose of the Study:

• To investigate novel regulatory mechanisms controlling Stu2 function.
• To explore the role of Stu2 acetylation in regulating its various functions.
• To understand the impact of Stu2 acetylation on chromosome stability and microtubule dynamics.

Main Methods:

• Site-directed mutagenesis to create acetyl-mimetic and acetyl-blocking Stu2 mutants.
• Analysis of chromosome stability and benomyl resistance in mutant strains.
• In silico modeling to predict Stu2 interactions.
• Assessment of Stu2 interactions with γ-tubulin.

Main Results:

• Acetylation of three lysine residues (K252, K469, K870) in distinct Stu2 domains was identified as a novel regulatory mechanism.
• Mutations altering Stu2 acetylation did not affect its essential functions but decreased chromosome stability.
• Acetylation-mimetic mutants showed altered benomyl resistance and increased interactions with γ-tubulin, consistent with in silico modeling.
• Stu2 acetylation influences interactions at the SPB.

Conclusions:

• Stu2 acetylation is a critical regulatory mechanism governing its functions.
• Acetylation impacts Stu2-mediated chromosome stability and interactions at the SPB.
• This study provides new insights into the post-translational regulation of microtubule-associated proteins.