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Point mutations impairing cell surface expression of the common beta subunit (CD18) in a patient with leukocyte adhesion molecule (Leu-CAM) deficiency.

Authors: Arnaout, MA  Dana, N  Gupta, SK  Tenen, DG  Fathallah, DM 
Citation: Arnaout MA, etal., J Clin Invest. 1990 Mar;85(3):977-81.
Pubmed: (View Article at PubMed) PMID:1968911
DOI: Full-text: DOI:10.1172/JCI114529

The leukocyte adhesion molecules CD11a/CD18, CD11b/CD18, and CD11c/CD18 (Leu-CAM) are members of the integrin receptor family and mediate crucial adhesion-dependent functions in leukocytes. The molecular basis for their deficient cell surface expression was sought in a patient suffering from severe and recurrent bacterial infections. Previous studies revealed that impaired cell surface expression of Leu-CAM is secondary to heterogeneous structural defects in the common beta subunit (CD18). Cloning and sequencing of complementary DNA encoding for CD18 in this patient revealed two mutant alleles, each representing a point mutation in the coding region of CD18 and resulting in an amino acid substitution. Each mutant allele results in impaired CD18 expression on the cell surface membrane of transfected COS M6 cells. One substitution involves an arginine residue (Arg593----cysteine) that is conserved in the highly homologous fourth cysteine-rich repeats of other mammalian integrin subfamilies. The other substitution involves a lysine residue (Lys196----threonine) located within another highly conserved region in integrins. These data identify crucial residues and regions necessary for normal cell surface expression of CD18 and possibly other integrin beta subunits and define a molecular basis for impaired cell surface expression of CD18 in this patient.

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CRRD Object Information
CRRD ID: 1600220
Created: 2007-03-05
Species: All species
Last Modified: 2007-03-05
Status: ACTIVE



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RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.