On the surface of myeloid progenitor cells, monocytes, macrophages, and microglia, CD33 Siglec (Siglec-3) is expressed. In contrast to conserved Siglecs, CD33 Siglec and CD33-related Siglecs appear to have developed fast through a variety of pathways, leading to significant changes in CD33-related Siglecs libraries in mammalian species.
Most cytosolic immunoreceptor tyrosine-based inhibitory motifs (ITIM) are present in human Siglecs. However, some Siglecs carry some basic amino acids that can detect molecules encoding tyrosine-based activation motifs (ITAMs) for signaling activation even though they lack intracellular domains. CD33 has a V Ig-like domain, a C2 Ig-like domain, a transmembrane domain, and a cytoplasmic tail with two conserved. CD33 is the only Siglec with a peroxisome targeting sequence in the cytoplasmic tail.
Fig.1 Structure of the immune D33. (PDB)
In the human sialic-acid binding Siglec family, there are 10 CD33-related members: CD33 (Siglec-3), Siglec-5~11, Siglec-14, and Siglec-16. Siglec-13 had been deleted from CD33-related members. Sialic Acid-Specific Lectin Analysis is a tool you can find in CD BioGlyco to help study functions of CD33-related Siglecs.
Fig.2 Schematic drawing of human and murine Siglec receptors. (Läubli & Varki, 2019)
Myeloid progenitor cell marker CD33 has the potential to control cell proliferation and/or differentiation. Later stages of hematopoiesis seem to see the expression of additional CD33-related Siglecs. Siglecs that are related to CD33 is also crucial for controlling leukocyte behavior because they promote the release of pro-inflammatory cytokines and suppress cell activation, proliferation, and death. Based on this, more and more Siglec Related Therapies are studied and applied. CD BioGlyco provides Targeting Carbohydrate-Lectin Interactions, Targeting Carbohydrates of Pathogens, and other Custom Glycosylation Services for customers to study CD33-related therapies.
CD BioGlyco is particularly interested in Lectins-related research fields, and we have a strong platform to provide relevant technical support to our customers. If you are interested in our services please contact us, our excellent service team looks forward to receiving your inquiries.