[Functional diversification of cytoplasmic actin isoforms]

The actin family consists of highly conservative proteins, abundant in all eukaryotic cells. Actin plays different roles in cell functioning including cell motility, maintenance of cell shape, signal transduction and transcription. The beta and y cytoplasmic actins are ubiquitously present in all cell types and are essential for cell survival. They differ only by four amino acids located at the N-terminus of the polypeptide chain. The proportion of cytoplasmic actins varies and depends on the cell type. In addition, it changes in pathological conditions. There is also some evidence that beta and gamma actins are located in different cytoplasmic areas, what suggests functional differences between them. Studies conducted in recent years, demonstrating the increase or reduction of cytoplasmic actin isoforms expression allow for better understanding of the role of these proteins in cell functioning. In this article, we present contemporary view on this subject.