CAS1 domain-containing protein 1 (CASD1)

CAS1 domain-containing protein 1 (CASD1) is a membrane-associated **enzyme** located in the Golgi apparatus that catalyzes the **O-acetylation** of sialic acids at the C7 and/or C9 positions, a modification critical for generating 9-O-acetylated sialoglycans[1][3][4][5]. The **transferase activity** of CASD1 uses acetyl-CoA as a donor and involves a catalytic triad in its N-terminal SGNH hydrolase-like domain, forming a transient acetyl–enzyme intermediate[1][3]. This enzymatic function is vital for normal sialoglycan biosynthesis, affecting cell–cell interaction, immune recognition, host–pathogen interaction, and tumor cell biology[1][3][4]. Genetic studies show that CASD1 is indispensable for the formation of 9-O-acetylated sialic acids in vivo[1][3]. Expression of CASD1 is found to be upregulated in some tumor cells and its gene expression profiling suggests potential for use as a disease biomarker[1][5]. There are currently no known direct drug modulators or established safety concerns directly associated with CASD1 as a therapeutic target.

Other names

N-acetylneuraminate (7)9-O-acetyltransferaseC7orf12NBLA04196Cas1pSOATFLJ21213FLJ21879Cas1Sialate O-acetyltransferaseCapsule synthesis 1

Catalyzes transfer of acetyl groups from acetyl-CoA to CMP-sialic acid, generating 9-O-acetylated sialoglycans[1][3]; Modulates recognition by lectins, immune receptors, and certain viruses due to altered sialic acid patterns