Delta-sarcoglycan

Delta-sarcoglycan (SGCD) is a 289-amino acid structural protein that functions as a component of the sarcoglycan complex, a subcomplex of the dystrophin-glycoprotein complex (UniProt: Q92629). This complex serves as a crucial link between the F-actin cytoskeleton and the extracellular matrix, providing mechanical stability to muscle cells.

In classical neuromuscular contexts, delta-sarcoglycan mutations cause autosomal recessive limb-girdle muscular dystrophy (LGMDR6) and dilated cardiomyopathy (CMD1L), both characterized by progressive muscle weakness or cardiac dysfunction (UniProt: Q92629). The protein is predominantly studied in skeletal and cardiac muscle physiology.

Delta-sarcoglycan shows elevated levels in Alzheimer's Disease brain tissue compared to age-matched controls (Chaparral AD proteomics: mean log2FC = +0.3448, upregulated). This modest but consistent increase was detected in human post-mortem AD brain proteomics analysis using tandem mass spectrometry across subcellular fractions. The functional significance of sarcoglycan upregulation in AD neurodegeneration remains to be determined.