Differential N-terminal processing of beta and gamma actin

• Published in: iScience 2022-10, Vol.25 (10), p.105186-105186, Article 105186
• Main Authors: Chen, Li, Vedula, Pavan, Tang, Hsin Yao, Dong, Dawei W., Kashina, Anna S.
• Format: Article
• Language: English
• Subjects: Cell biology; Functional aspects of cell biology
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2022.105186

Cytoplasmic beta- and gamma-actin are ubiquitously expressed in every eukaryotic cell. They are encoded by different genes, but their amino acid sequences differ only by four conservative substitutions at the N-termini, making it difficult to dissect their individual regulation. Here, we analyzed actin from cultured cells and tissues by mass spectrometry and found that beta, unlike gamma actin, undergoes sequential removal of N-terminal Asp residues, leading to truncated actin species found in both F- and G-actin preparations. This processing affects up to ∼3% of beta actin in different cell types. We used CRISPR/Cas-9 in cultured cells to delete two candidate enzymes capable of mediating this type of processing. This deletion abolishes most of the beta actin N-terminal processing and results in changes in F-actin levels, cell spreading, filopodia formation, and cell migration. Our results demonstrate previously unknown isoform-specific actin regulation that can potentially affect actin functions in cells. [Display omitted] •Intracellular beta actin is specifically processed by removal of N-terminal residues•N-terminally processed beta actin is found in both F- and G-actin pool•Deletion of N-aminopeptidases affects beta actin, cytoskeleton, and cell motility Cell biology; Functional aspects of cell biology