Sorting nexin 27 interactome in T-lymphocytes identifies zona occludens-2 dynamic redistribution at the immune synapse.

Abstract

T Lymphocyte recognition of antigens leads to the formation of a highly organized structure termed immune synapse (IS) by analogy with the neuronals synapse. Sorting nexin 27 (SNX27) controls the endosomal traffic of PSD95, Dlg1, ZO-1 (PDZ) domain-interacting proteins, and its alteration is associated with impaired synaptic function and neurological diseases. In T-lymphocytes, SNX27-positive vesicles polarize to the IS, the identity of SNX27 interactors in these conditions nonetheless remains unknown. Here we used proteomics to analyze the SNX27 interactome purified from IS-forming T cells, and confirmed the conserved nature of the SNX27/WASH/retromer association in hematopoietic cells. Furthermore, our comparative interactome analysis of SNX27 wild-type and a mutant-deficient for PDZ cargo recognition identified the epithelial cell-cell junction protein zona occludens-2 (ZO-2) as an IS component. Biochemistry and microscopy approaches in T cells confirmed SNX27/ZO-2 PDZ-dependent interaction, and demonstrated its role controlling the dynamic localization of ZO-2 at the IS. This study broadens our knowledge of SNX27 function in T lymphocytes, and suggests that pathways that delimit polarized structures in nervous and epithelial systems also participate in IS regulation.