CD33 Sialic-acid-binding immunoglobulin-like lectin (Siglec) that plays a role in mediating cell-cell interactions and in maintaining immune cells in a resting state. Preferentially recognizes and binds alpha-2,3- and more avidly alpha-2,6-linked sialic acid-bearing glycans. Upon engagement of ligands such as C1q or syalylated glycoproteins, two immunoreceptor tyrosine-based inhibitory motifs (ITIMs) located in CD33 cytoplasmic tail are phosphorylated by Src-like kinases such as LCK. These phosphorylations provide docking sites for the recruitment and activation of protein-tyrosine phosphatases PTPN6/SHP-1 and PTPN11/SHP-2. In turn, these phosphatases regulate downstream pathways through dephosphorylation of signaling molecules. One of the repressive effect of CD33 on monocyte activation requires phosphoinositide 3-kinase/PI3K. Belongs to the immunoglobulin superfamily. SIGLEC (sialic acid binding Ig-like lectin) family. Monocytic/myeloid lineage cells. In the brain, CD33 is mainly expressed on microglial cells. 3 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Protein type: Cell adhesion; Membrane protein, integral
Chromosomal Location of human Ortholog: 19q13.41
Cellular Component:  external side of plasma membrane; Golgi apparatus; nucleoplasm; peroxisome; plasma membrane; specific granule membrane; tertiary granule membrane
Molecular Function:  carbohydrate binding; protein binding; protein phosphatase binding; sialic acid binding; signaling receptor activity
Biological Process:  cell adhesion; cell-cell adhesion; cell-cell signaling; immune response-inhibiting signal transduction; negative regulation of calcium ion transport; negative regulation of cell population proliferation; negative regulation of interleukin-1 beta production; negative regulation of interleukin-8 production; negative regulation of monocyte activation; negative regulation of tumor necrosis factor production; positive regulation of protein secretion; positive regulation of protein tyrosine phosphatase activity; signal transduction
Reference #:  P20138 (UniProtKB)
Alt. Names/Synonyms: CD33; CD33 antigen (gp67); CD33 molecule; CD33 molecule transcript; FLJ00391; gp67; Myeloid cell surface antigen CD33; p67; sialic acid binding Ig-like lectin 3; Sialic acid-binding Ig-like lectin 3; Siglec-3; SIGLEC3
Gene Symbols: CD33
Molecular weight: 39,825 Da
Basal Isoelectric point: 8.68  Predict pI for various phosphorylation states
Protein-Specific Antibodies, siRNAs or Recombinant Proteins from Cell Signaling Technology® Total Proteins
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CD33

Protein Structure Not Found.


Cross-references to other databases:  AlphaFold  |  STRING  |  cBioPortal  |  Wikipedia  |  neXtProt  |  Protein Atlas  |  BioGPS  |  Pfam  |  RCSB PDB  |  Phospho.ELM  |  NetworKIN  |  GeneCards  |  UniProtKB  |  Entrez-Gene  |  GenPept  |  Ensembl Gene  |  Ensembl Protein