Distribution of dystrophin- and utrophin-associated protein complexes during activation of human neutrophils

Objective

Dystrophins, utrophins, and their associated proteins are involved in structural and signaling roles in nonmuscle tissues; however, description of these proteins in neutrophils remained unexplored. Therefore we characterize the pattern expression, and the cellular distribution of dystrophin and utrophin gene products and dystrophin-associated proteins (i.e., β-dystroglycan, α-syntrophin, and α-dystrobrevins) in relation to actin filaments in resting and activated with formyl-methionyl-leucyl-phenylalanine human neutrophils.

Materials and Methods

Resting and fMLP-activated human neutrophils were analyzed by immunoblot and by confocal microscopy analysis. Immunoprecipitation assays were performed to corroborate the presence of protein complexes.

Results

Immunoprecipitation assays and confocal analysis demonstrated the presence of two dystrophin-associated protein complexes in resting and activated neutrophils: the former formed by Dp71d/Dp71Δ₁₁₀^m and dystrophin-associated proteins (β-dystroglycan, α-syntrophin, α-dystrobrevin-1, and -2), while the latter contains Up400, instead of Dp71d/Dp71Δ₁₁₀^m, as a central component of the dystrophin-associated protein complexes (DAPC). Confocal analysis also showed the subcellular redistribution of Dp71d/Dp71Δ₁₁₀^m∼DAPC and Up400∼DAPC in F-actin−based structures displayed during activation process with fMLP.

Conclusions

Our study showed the existence of two protein complexes formed by Dp71d/Dp71Δ₁₁₀^m or Up400 associated with DAPs in resting and fMLP-treated human polymorphonuclears. The interaction of these complexes with the actin cytoskeleton is indicative of their dynamic participation in the chemotaxis process.