Siglec-3/CD33 Protein, Human (HEK293, His-Avi)

Siglec-3/CD33 protein is a sialic acid-binding lectin that mediates cell-cell interactions and maintains immune cell quiescence. It prefers α-2,3- and α-2,6-linked glycans with sialic acid. Siglec-3/CD33 Protein, Human (HEK293, His-Avi) is the recombinant human-derived Siglec-3/CD33 protein, expressed by HEK293 , with C-Avi, C-His labeled tag. The total length of Siglec-3/CD33 Protein, Human (HEK293, His-Avi) is 242 a.a., with molecular weight of 52-60 kDa.

The Siglec-3/CD33 protein, a sialic-acid-binding immunoglobulin-like lectin, plays a crucial role in mediating cell-cell interactions and maintaining immune cells in a resting state. It exhibits a preference for recognizing and binding alpha-2,3- and more avidly alpha-2,6-linked sialic acid-bearing glycans. Upon engagement with ligands like C1q or sialylated glycoproteins, two immunoreceptor tyrosine-based inhibitory motifs (ITIMs) within CD33's cytoplasmic tail undergo phosphorylation by Src-like kinases such as LCK. These phosphorylated ITIMs serve as docking sites for recruiting and activating protein-tyrosine phosphatases PTPN6/SHP-1 and PTPN11/SHP-2, which, in turn, regulate downstream pathways through dephosphorylation of signaling molecules. CD33's repressive effect on monocyte activation involves phosphoinositide 3-kinase/PI3K. Structurally, the protein forms homodimers through disulfide linkages and interacts with PTPN6/SHP-1 and PTPN11/SHP-2 upon phosphorylation. It also engages with C1QA via its C-terminus, activating CD33 inhibitory motifs.

Human

HEK293

C-Avi;C-His

P20138 (D18-H259)

945  [NCBI]

52-60 kDa

Greater than 95% as determined by Tris-Bis PAGE.

<1 EU/μg, determined by LAL method.