ASAH1 Protein, Human (His-SUMO)

ASAH1, a lysosomal ceramidase, functions in sphingolipid metabolism by hydrolyzing sphingolipid ceramides into sphingosine and free fatty acids under acidic pH conditions. Ceramides, sphingosine, and sphingosine-1-phosphate are bioactive lipids that play crucial roles in cellular signaling pathways governing processes such as cell proliferation, apoptosis, and differentiation. ASAH1 exhibits higher catalytic efficiency towards C12-ceramides compared to other ceramides and can also catalyze the reverse reaction, synthesizing ceramides from fatty acids and sphingosine. In this synthetic reaction, the natural sphingosine D-erythro isomer is more efficiently utilized, with fatty acids of chain lengths 12 or 14 carbons being the most effective substrates. Additionally, ASAH1 displays N-acylethanolamine hydrolase activity. By regulating ceramide, sphingosine, and sphingosine-1-phosphate levels, ASAH1 mediates calcium-induced differentiation of epidermal keratinocytes. It indirectly regulates tumor necrosis factor (TNF)-induced apoptosis and, in adrenocortical cells, likely serves as a regulator of steroidogenesis by maintaining the intracellular balance between ceramides and sphingosine. Furthermore, ASAH1 may directly impact steroidogenesis by binding to the nuclear receptor NR5A1 and negatively regulating its transcriptional activity.