The unique localization of ZFP185 at uropod of mouse T lymphocytes.

Zinc finger protein 185 (ZFP185), which contains a conservative Lin-l 1, Isl-1 and Mec-3 (LIM) domain at its C-terminus, is a member of mouse LIM protein family. Although brahma-related gene 1(BRG1), the upstream regulation gene of ZFP185, is essential in the development and activation of T lymphocytes, there is no report on the involvement of ZFP185 in lymphocyte activation. The expression of ZFP185 protein was up-regulated significantly in T lymphocytes during their activation by phorbol 12-myristate 13-acetate (PMA)/ionomycin, compared with non-activated T lymphocytes, as determined by western blot assays. However, over-expression of ZFP185 in EL4 cells showed no significant effect on the cell proliferation. Importantly, expression of ZFP185-enhanced green fluorescent protein fusion protein in EL4 cells showed that ZFP185 uniquely localized in the uropod of lymphocytes as observed with a two-photon laser scanning confocal microscope. The direct interaction between ZFP185 and actin was supported by co-immunoprecipitation and immunofluorescence assays. The special distribution of ZFP185 in uropod indicates the potential involvement of ZFP185 in T-cell morphology and movement.