Actin's C-terminus coordinates actin structural changes and functions

Actin is essential to eukaryotic cellular processes. Actin's C-terminus appears to play a direct role in modulating actin's structure and properties, facilitating the binding and function of actin-binding proteins (ABPs). The structural and functional characterization of filamentous actin's C-terminus has been impeded by its inherent flexibility, as well as actin's resistance to crystallization for x-ray diffraction and the historical resolution constraints associated with electron microscopy. Many biochemical studies have established that actin's C-terminus must retain its flexibility and structural integrity to modulate actin's structure and functions. For example, C-terminal structural changes are known to affect nucleotide binding and exchange, as well as propagate actin structural changes throughout extensive allosteric networks, facilitating the binding and function of ABPs. Advances in electron microscopy have resulted in high-resolution structures of filamentous actin, providing insights into subtle structural changes that are mediated by actin's C-terminus. Here, we review existing knowledge establishing the importance of actin's C-terminus within actin structural changes and functions and discuss how modern structural characterization techniques provide the tools to understand the role of actin's C-terminus in cellular processes.

Automated summary

Actin is crucial for eukaryotic cellular processes, and its C-terminus directly modulates actin's structure and properties to facilitate the binding and function of actin-binding proteins (ABPs). Previous challenges in characterizing the C-terminus have been overcome with advances in electron microscopy, providing high-resolution structures and insights into subtle structural changes mediated by actin's C-terminus. This review discusses the importance of actin's C-terminus in actin structural changes and functions, and highlights how modern structural characterization techniques aid in understanding its role in cellular processes.