Characterization of a new disease-causing mutation of SH2D1A in a family with X-linked lymphoproliferative disease.
Males with an expressed mutation in the SH2D1A gene that encodes an SH2 domain protein named SH2D1A or SAP (NP_002342; signaling lymphocyte activating molecule [SLAM]-associated protein), have an X-linked syndrome characterized by an increased vulnerability to infection with Epstein-Barr virus (EBV). We evaluated two related male patients with fatal infectious mononucleosis (FIM) and mutation in the SH2D1A gene. Sequence analysis revealed a hemizygous c.47G>A mutation in one of the patients, and heterozygosity for this mutation in the genomic DNA from his mother and maternal grandmother. This mutation resulted in p.G16D amino acid change in the sequence of the SAP protein. To analyze the effect of this missense mutation on protein function cDNA was generated by site-directed mutagenesis and expressed in COS cells. We found that half-life of the p.G16D protein was comparable to that of wild type SAP. However, the mutant protein was defective in binding to its physiological ligands SLAM and 2B4. These results suggest that a defect in ligand binding contributes to the loss of function of the SAP protein in patients carrying p.G16D mutation.
Erdõs
Melinda
M
Department of Infectology and Pediatric Immunology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.
Uzvölgyi
Eva
E
Nemes
Zoltán
Z
Török
Olga
O
Rákóczi
Eva
E
Went-Sümegi
Nils
N
Sümegi
János
J
Maródi
László
L
D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D019556:COS Cells; D002648:Child; D002522:Chlorocebus aethiops; D020022:Genetic Predisposition to Disease; D006023:Glycoproteins / Q000378:metabolism; D006207:Half-Life; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism; D007244:Infectious Mononucleosis / Q000235:genetics*; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D008232:Lymphoproliferative Disorders / Q000235:genetics*; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D010375:Pedigree; D011485:Protein Binding / Q000502:physiology; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic / Q000378:metabolism; D000071179:Signaling Lymphocytic Activation Molecule Associated Protein; D000071176:Signaling Lymphocytic Activation Molecule Family; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1
D015703:Antigens, CD; C084093:CD244 protein, human; D006023:Glycoproteins; D007136:Immunoglobulins; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; C114953:SH2D1A protein, human; D000071179:Signaling Lymphocytic Activation Molecule Associated Protein; D000071176:Signaling Lymphocytic Activation Molecule Family; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1