Although several cell polarity proteins have been characterized in lymphocytes [4, 5] , PALS1 expression in T cells remains to be determined [8] . To address this question, we first performed RT-PCR analysis on resting human CD3 + T cells and Jurkat lymphocytes extracts, and detected mRNA for PALS1 ( Figure 1A ). These mRNA were efficiently translated into protein, as antibodies against PALS1 detected a band, which was absent from PALS1-siRNA transfected primary T lymphocytes lysates ( Figure 1B ). Similar results were obtained with Jurkat T cells ( Figure 1B ). Of note, PALS1 levels remained unchanged in cells stimulated with antibodies to CD3 and CD28, or with PMA and ionomycin ( Figure 1C ). We next investigated PALS1 subcellular location by confocal microscopy. In contrast to epithelial cells where it accumulate to tight junctions [12] , PALS1 did not reach membrane domains and remains essentially cytosolic with punctuate structures. Additional staining revealed that these structures coalesced with the Golgi apparatus ( Figure 1D and Figure S1 ). Accordingly, Brefeldin A-triggered disassembly of the Golgi apparatus also disrupted PALS1 punctuate structures ( Figure 1D ). This is reminiscent of PALS1 relocation to the Golgi apparatus in cells infected with SARS coronovirus [19] . Last, we observed that TCR-mediated stimulation only promoted a discrete redistribution of PALS1 within the cytosol of Jurkat cells ( Figure S1 ). Altogether, our results suggest that similarly to Dlgh1, SCRIB, CRB3, and PKCf [4, 5] , the cell polarity protein PALS1 is expressed in lymphocytes at both mRNA and protein level.