| First Author | Kurita S | Year | 2007 |
| Journal | Genes Cells | Volume | 12 |
| Issue | 5 | Pages | 663-76 |
| PubMed ID | 17535256 | Mgi Jnum | J:127110 |
| Mgi Id | MGI:3762990 | Doi | 10.1111/j.1365-2443.2007.01078.x |
| Citation | Kurita S, et al. (2007) Actin filaments-stabilizing and -bundling activities of cofilin-phosphatase Slingshot-1. Genes Cells 12(5):663-76 |
| abstractText | Slingshot-1 (SSH1) is known to regulate actin filament dynamics by dephosphorylating and activating cofilin, an actin-depolymerizing factor. SSH1 binds to filamentous (F-) actin through its multiple F-actin-binding sites and its cofilin-phosphatase activity is enhanced by binding to F-actin. In this study, we demonstrate that SSH1 has F-actin-stabilizing and -bundling activities. In vitro actin depolymerization assays revealed that SSH1 suppressed spontaneous and cofilin-induced actin depolymerization in a dose-dependent manner. SSH1 inhibited F-actin binding and severing activities of cofilin. Low-speed centrifugation assays combined with fluorescence and electron microscopic analysis revealed that SSH1 has F-actin-bundling activity, independently of its cofilin-phosphatase activity. Deletion of N- or C-terminal regions of SSH1 significantly reduced its F-actin-stabilizing and -bundling activities, indicating that both regions are critical for these functions. As SSH1 does not form a homodimer, it probably bundles F-actin through its multiple F-actin-binding sites. Knockdown of SSH1 expression by RNA interference significantly suppressed stress fiber formation in C2C12 myoblast cells, indicating a role for SSH1 in stress fiber formation or stabilization in cells. SSH1 thus has the potential to regulate actin filament dynamics and organization in cells via F-actin-stabilizing and -bundling activities, in addition to its ability to dephosphorylate cofilin. |
