Plant Actin-Depolymerizing Factors Possess Opposing Biochemical Properties Arising from Key Amino Acid Changes...

Area of Science:

• Molecular Biology
• Evolutionary Biology
• Plant Science

Background:

• Actin-depolymerizing factors (ADFs) are crucial actin-binding proteins regulating cytoskeletal dynamics.
• Plant ADFs exhibit diverse biochemical properties, but the mechanisms of their functional divergence are largely unknown.

Purpose of the Study:

• To investigate the biochemical functions of 11 Arabidopsis thaliana ADF genes.
• To identify the molecular mechanisms underlying functional divergence in plant ADFs.

Main Methods:

• In vitro biochemical analyses of 11 Arabidopsis ADFs.
• Tracking historical mutation sites on ancestral proteins.
• Investigating the role of N-terminal extensions in ADF function.

Main Results:

• All 11 Arabidopsis ADFs displayed opposing biochemical properties.
• Subclass III ADFs evolved actin bundling (B-type) from depolymerizing (D-type) function; subclass I ADFs showed enhanced D-type function.
• Conserved mutations and N-terminal extensions from intron-sliding events were key to functional divergence.

Conclusions:

• Plant ADF functional divergence is conserved across angiosperms.
• N-terminal extensions are essential for the evolution of B-type ADF function.
• Evolutionary changes in ADFs, including N-terminal extensions and mutations, generated diverse biochemical activities from a common ancestor.