The
dystrophin-associated protein complex (
DAPC) is a multimeric complex that links the extracellular matrix to the actin cytoskeleton, and in some cases
dystrophin can be substituted by its autosomal homologue
utrophin to form the
utrophin-associated
protein complex (UAPC). Both complexes maintain the stability of plasma membrane during contraction process and play an important role in transmembrane signaling. Mutations in members of the
DAPC are associated with
muscular dystrophy and
dilated cardiomyopathy. In a previous study with human umbilical cord vessels, we observed that
utrophin colocalize with
caveolin-1 (Cav-1) which proposed the presence of UAPC in the plasma membrane of vascular smooth muscle (VSM). In the current study, we demonstrated by immunofluorescence analysis, co-immunoprecipitation assays, and subcellular fractionation by
sucrose gradients, the existence of an UAPC in
lipid raft domains of human umbilical artery smooth muscle cells (HUASMC). This complex is constituted by
utrophin, β-DG, ε-SG, α-smooth muscle actin, Cav-1,
endothelial nitric oxide synthase (eNOS) and cavin-1. It was also observed the presence of
dystrophin,
utrophin Dp71, β-SG, δ-SG, δ-SG3 and sarcospan in non-
lipid raft fractions. Furthermore, the knockdown of α/β-DG was associated with the decrease in both the synthesis of
nitric oxide (NO) and the presence of the phosphorylated (active) form of eNOS; and with a reduction in the downstream activation of some cGMP signaling transduction pathway components. Together these results show the presence of an UAPC complex in HUASMC that may participate in the activity regulation of eNOS and in the vascular function.