Colocalization Analysis of Cytoplasmic Actin Isoforms Distribution in Endothelial Cells

• Published in: Biomedicines Vol. 10; no. 12; p. 3194
• Main Authors: Shakhov, Anton S, Kovaleva, Polina A, Churkina, Alexandra S, Kireev, Igor I, Alieva, Irina B
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.12.2022; MDPI
• Subjects: Actin; actin cytoskeleton; Amino acid sequence; Cell activation; Correlation analysis; Cytoplasm; Cytoskeleton; endothelial cell; Endothelial cells; Endothelium; Epithelial cells; Fibroblasts; Isoforms; Microscopy; Monoclonal antibodies; Nocodazole; non-muscle actin isoforms; Physiological aspects; Proteins; Pulmonary arteries; Signal transduction; super resolution microscopy; Tumors; β-actin; γ-actin; Russia; actin cytoskeleton; γ-actin; non-muscle actin isoforms; colocalization analysis; endothelial cell; β-actin; super resolution microscopy
• ISSN: 2227-9059; 2227-9059
• DOI: 10.3390/biomedicines10123194

Actin cytoskeleton is an essential component of living cells and plays a decisive role in many cellular processes. In mammals, β- and γ-actin are cytoplasmic actin isoforms in non-muscle cells. Despite minor differences in the amino acid sequence, β- and γ-actin localize in different cell structures and perform different functions. While cytoplasmic β-actin is involved in many intracellular processes including cell contraction, γ-actin is responsible for cell mobility and promotes tumor transformation. Numerous studies demonstrate that β- and γ-actin are spatially separated in the cytoplasm of fibroblasts and epithelial cells; this separation is functionally determined. The spatial location of β/γ-actin in endothelial cells is still a subject for discussion. Using super-resolution microscopy, we investigated the β/γ-actin colocalization in endotheliocytes and showed that the β/γ-actin colocalization degree varies widely between different parts of the marginal regions and near the cell nucleus. In the basal cytoplasm, β-actin predominates, while the ratio of isoforms evens out as it moves to the apical cytoplasm. Thus, our colocalization analysis suggests that β- and γ-actin are segregated in the endotheliocyte cytoplasm. The segregation is greatly enhanced during cell lamella activation in the nocodazole-induced endothelial barrier dysfunction, reflecting a different functional role of cytoplasmic actin isoforms in endothelial cells.