PTEN expression. Mouse neutrophils or A3 Jurkat cells (5 × 105) were lysed in SDS sample buffer and blotted with the anti-PTEN antibody. The PTEN antibody primarily detects a band corresponding to the size of PTEN in mouse neutrophils, but not in the A3 cells acquired from ATCC.

In the letter by Li et al. (Nature Cell Biol. 7, 399–404; 2005), the identity of the 'Jurkat cells' used was incorrect. These cells, now referred to as J1 cells, express PTEN (Fig. S3a of the original publication), unlike A3 Jurkat cells (see figure below, which also demonstrates the specificity of the PTEN antibody used for this study) and E6 Jurkat cells (data not shown) obtained from ATCC (Manassas, VA).

Cell-surface marker analyses reveal that J1 cells express the B-cell markers CD45R and CD19, but not the T-cell markers CD3 or CD4; A3 and E6 cells, in contrast, express CD3 and CD4.

Although this does not affect the fundamental conclusion of our report, we deeply regret any confusion caused by this mistaken identity.