|CD18||ITGβ2 (integrin β2, complement component 3 receptor 3 and 4), β2 integrin chain, CD11a β subunit, CD11b β subunit, CD11c β subunit|
|Molecule Type||Antigen Expression||Molecular Weight|
Min / Max
|Non-lineage Restricted Molecule|
Type 1 glycoprotein
|Leukocyte||95 / 95|
120 / 120
|CD18 is expressed on all leukocytes. It is the β2 integrin chain of the CD11a, CD11b, CD11c heterodimers. |
|MOLECULAR FAMILY NAME: Belongs to the integrin b chain family.|
CD18 is a single-pass type-1 747 aa glycoprotein. It contains a 678 aa extracellular domain which contains an I-domain, 6 potential N-linked glycosylation sites and a heavily internally cross-linked with 28 potential disulphide links, a 23 aa transmembrane domain and a 46 aa cytoplasmic domain. The N-terminus of CD18 is blocked.
POST-TRANSCRIPTIONAL MODIFICATION: No information.
POST-TRANSLATIONAL MODIFICATION: No information.
|LIGANDS AND MOLECULES ASSOCIATED WITH CD18|
CD18 is associated with and see CD11a, CD11b and CD11c.
|It is the β2 integrin chain of the CD11a, CD11b, CD11c heterodimers. CD18 is expressed on an a chain and a b chain. CD18 combines with the a L chains CD11a to form the integrin LFA-1 and with the CD11b a chain to form the integrin Mac-1. The integrins are known to participate in cell adhesion and cell-surface mediating signaling in leukocytes, the hematopoietic system. CD18 is involved in cell-cell and cell-matrix interactions being a member of a family of cell surface proteins. CD18 may be important in the regulation of ligand binding activities of various CD11/CD18 complexes. It interacts noncavalently with CD11a, b, c and d to form the adhesion molecule complexes LFA-1, Mac-1, p150, p95 and 2Db2 respectively. CD18 has been shown to interact with several cytoskeletal proteins including a-actinin and filamin ABP-280, and the cytoplasmic regulatory molecule cytoadhesin-1. There are also a number of antibodies that promote the CD11/CD18 antigens to a high affinity binding to ligands. Leukocyte adhesion deficiency (LAD) results from defects in the CD18 gene, leading to diminished expression of all CD18-containing integrins. The deficiency is very heterogeneous with varying degrees of clinical severity. The gene defect has been observed in humans, cattle, and dogs. |
BIOCHEMICAL ACTIVITY: No information.
DISEASE RELEVANCE AND FUNCTION OF CD18 IN INTACT ANIMAL
LAD-1 is caused by a lesion in the CD18 gene coding for the common b2 subunit causing patients to suffer from recurrent infections. General importance in inflammatory responses has been tested in CD18 "knockout" mice.
|MOLECULAR EXPRESSION -|
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD18: No information.
SUBSTRATES: No information.
ENZYMES WHICH MODIFY CD18: No information.
Database accession numbers
Revised June 25, 2008