Drebrin-like protein regulates body bending ofC. elegansvia suppression of NCA cation leak channels

Abstract

Drebrin-like protein (DBN-1) in C. elegans is an adaptor protein that connects different cellular pathways to the actin cytoskeleton. Using a CRISPR-Cas9 system, we generated a new dbn-1 allele, which lacks 80% of C-terminal part of DBN-1. The mutant displays a striking hyper-bending locomotion phenotype and body posture with two times stronger curvature than wild type. We show by atomic force microscopy that the muscle tone of the mutant remains unaffected. Aiming to track down the cause of hyper-bending, we performed genetic epistasis experiments. We found that mutations in the Rho-specific guanine-nucleotide exchange factor (GEF) domain of UNC-73 (Trio), pan-neuronal expression of dominant negative RHO-1 and mutations in NCA (NALCN) cation leak channels all suppressed hyper-bending in the dbn-1 mutant. These data indicate that DBN-1 negatively regulates the activity of both NCA-1 and NCA-2 channels, opposing RHO-1 in the

Dimerization of Human Drebrin-like Protein Governs Its Biological Activity

“…It can be possible that other actin-binding proteins with higher F-actin binding affinity displace truncated DBNL from actin filaments in live cells. Previous reports demonstrate the importance of the native structure of DBNL for retaining its biological activity. ,,,, In cells, DBNL undergoes proteolysis by the ubiquitous calcium-sensitive protease calpain-2, which cleaves DBNL between the coiled coil and the proline-rich region . Here, the N-terminal fragment (consisting of two actin-binding modules) alone cannot rescue formation of actin-based dorsal ruffles in DBNL-deficient cells .…”

“…In C. elegans , the impact of truncations can be visually evaluated by the change in the worm’s movement ability. While the dbn-1­(vit7) mutant, containing a premature stop codon after the largest part of the ADF-H domain, displays a strong body curvature and a striking hyperbending phenotype, the dbn-1­(ok925) mutant truncated after two coiled coils moves in sinusoidal waves similar to the wild type . However, the ok925 gene has a mild disorganization of actin filaments during body-wall muscle contraction and defective vesicle scission during endocytosis in the intestines .…”