Figure 1.
Mutation of T195P on CD28. (A) Representative sequencing traces of wild-type and T195P mutant CD28. Threonine (ACT) was changed to proline (CCT) at the 195th amino acid of CD28. (Top) Sequence from wild-type genomic DNA. (Bottom) Sequence from an AITL sample. Arrows and red letters note the location of the base change. The mutant sequence trace shows heterozygosity. (B) Mutation position and functional domains of the CD28 protein. PI3-K (p110δ/p85): GRB2 and GRAP2 bind to phosphorylated YMNM motif in cytoplasmic region of CD28. The red letter denotes the mutated threonine. TM, transmembrane domain. (C) The genomic DNA of CD28 from lymphoma patients was analyzed by PCR amplification and Sanger sequencing. The mutation of CD28 T195P was detected in 5 (10.2%) of 49 AITL patients, in 0 (0%) of 39 PTCL patients and 0 (0%) of 37 NK/T patients.