Table 1. The characteristics of the BTK variants.
| BTK and variants | Protein | BTK Y551 phosphorylationa | Intracellular BTK Y223 and PLCγ2 Y753 phosphorylationa | IVK BTK Y223 and PLCγ2 Y753 phosphorylationa | Ibrutinib sensitivity |
|---|---|---|---|---|---|
| Cysteine (WT) | Detectable | ++++ | ++++ | ++++ | Yes |
| Serine | Detectable | ++++ | ++++ | ++++ | No |
| Threonine | Detectable | +++ | +++ | +++ | No |
| Glycine | Detectable | ++ | + | — | NR |
| Tyrosine | Detectable | — | — | — | NR |
| Tryptophan | Detectable | — | — | — | NR |
| Phenylalanine | Detectable | — | — | — | NR |
| Arginine | Detectable | — | — | — | NR |
Abbreviations: IVK, in vitro kinase assay; NR, not relevant; WT, wild-type BTK.
a
Intensity scoring based on visual inspection.