PTPN22 regulates T cell synapse formation through PSTPIP1-dependent actin remodeling

Authors:
Publisher website
Google Scholar
Abstract
Protein tyrosine phosphatase nonreceptor type 22 (PTPN22) is a key negative regulator of T cell activation, acting with C-terminal Src kinase (Csk) to suppress early T cell receptor (TCR) signaling and maintain immune tolerance. Given that the autoimmune disease–associated R620W variant alters T cell responses, we investigated the effects of PTPN22 on T cell activation. We identified a role for PTPN22 in modulating cytoskeletal dynamics at the immunological synapse in Jurkat cells through its interaction with proline-serine-threonine phosphatase–interacting protein 1 (PSTPIP1), a cytoskeletal adaptor protein that recruits actin nucleation–promoting factors, including WASp, to the TCR. PTPN22 deficiency or inhibition disrupted Arp2/3-dependent actin remodeling, leading to excessive central F-actin foci, PSTPIP1 mislocalization, and enhanced Ca 2+ signaling, especially under low-affinity stimulation of the TCR. Super-resolution DNA-PAINT analysis revealed that loss of PTPN22 promoted aberrant PSTPIP1-TCR nanoscale colocalization and increased TCR clustering. These findings uncover a PTPN22-PSTPIP1 signaling axis that is critical for regulating cytoskeletal remodeling and receptor organization, providing insights into T cell hyperactivation that may be relevant to autoimmune disease.
Funding Information
  • Chan Zuckerberg Initiative (2023-321188)
  • Kennedy Trust for Rheumatology Research (20525)
  • Engineering and Physical Sciences Research Council (EP/R513143/1)
  • Engineering and Physical Sciences Research Council (EP/T517793/1)
  • Biotechnology and Biological Sciences Research Council (BB/T008709/1)
  • Biotechnology and Biological Sciences Research Council (BB/Y513064/1)
  • Royal Society (DHF\R1\191019)
  • Royal Society (DHF\R\251006)
  • Human Frontier Science Program (LT0025/2023-C)
  • Great Ormond Street Institute of Child Health (20IC20)
  • Versus Arthritis (20525)

This publication has 45 references indexed in Scilit: