Glucosylceramide synthase (GCS) is a key enzyme in lipid synthesis, belonging to the family of ceramide synthases, specifically catalyzing the formation of ceramides. This membrane-bound enzyme comprises specific catalytic subunits and regulatory subunits, and is found in the Golgi apparatus and endoplasmic reticulum, crucial for cell membrane construction and signal transduction. GCS regulates cell growth, differentiation, apoptosis, and other responses through the synthesis of ceramides. Its gene expression is tissue-specific across various cell types and tissues, correlated with the development of multiple diseases. Mutations or abnormal expression of the gene affect lipid metabolism, thereby interfering with cellular functions.