A Scoping Review of Sarcoglycan Expression in Non-Muscle Organs: Beyond Muscles

Abstract

This scoping review explores the expression patterns and molecular features of sarcoglycans (SGs) in non-muscle organs, challenging the long-standing assumption that their function is confined to skeletal and cardiac muscle. By analyzing evidence from both animal models and human studies, the review highlights the widespread presence of SG subunits in organs, including the nervous system, glands, adipose tissue, oral mucosa, retina, and other structures, with distinct regional and cell-type-specific patterns. Studies on the central nervous system demonstrate a widespread "spot-like" distribution of SG subunits in neurons and glial cells, implicating their involvement in synaptic organization and neurotransmission. Similarly, SGs maintain cellular integrity and homeostasis in glands and adipose tissue. At the same time, the altered expression of SGs is associated with pathological conditions in the gingival epithelium of the oral mucosa. These findings underscore the multifaceted roles of SGs beyond muscle, suggesting that they may contribute to cellular signaling, membrane stability, and neurovascular coupling. However, significant gaps remain regarding SG post-translational modifications and functional implications in non-muscle organs. Future research integrating molecular, cellular, and functional approaches in animal models and human tissues is essential to fully elucidate these roles and explore their potential as therapeutic targets in various diseases.

Keywords: cell adhesion; epithelial signaling; non-muscle organ; sarcoglycans; synaptic organization; tissue homeostasis.

Figure 1

PRISMA flowchart summarizing the article selection process.

Figure 2

Expressions of SGs in non-muscle organs categorized by human and animal models (mouse, rat, and rabbit).

Figure 3

Heatmap summarizing the expression of SG subunits across non-muscle organs. Color intensity reflects the frequency of reported expression in the literature based on the number of studies identifying each SG subunit in a given organ.