| First Author | Lee HS | Year | 2022 |
| Journal | J Exp Med | Volume | 219 |
| Issue | 8 | PubMed ID | 35766979 |
| Mgi Jnum | J:331428 | Mgi Id | MGI:7329876 |
| Doi | 10.1084/jem.20211637 | Citation | Lee HS, et al. (2022) Phostensin enables lymphocyte integrin activation and population of peripheral lymphoid organs. J Exp Med 219(8):e20211637 |
| abstractText | Rap1 GTPase drives assembly of the Mig-10/RIAM/Lamellipodin (MRL protein)-integrin-talin (MIT) complex that enables integrin-dependent lymphocyte functions. Here we used tandem affinity tag-based proteomics to isolate and analyze the MIT complex and reveal that Phostensin (Ptsn), a regulatory subunit of protein phosphatase 1, is a component of the complex. Ptsn mediates dephosphorylation of Rap1, thereby preserving the activity and membrane localization of Rap1 to stabilize the MIT complex. CRISPR/Cas9-induced deletion of PPP1R18, which encodes Ptsn, markedly suppresses integrin activation in Jurkat human T cells. We generated apparently healthy Ppp1r18-/- mice that manifest lymphocytosis and reduced population of peripheral lymphoid tissues ascribable, in part, to defective activation of integrins alphaLbeta2 and alpha4beta7. Ppp1r18-/- T cells exhibit reduced capacity to induce colitis in a murine adoptive transfer model. Thus, Ptsn enables lymphocyte integrin-mediated functions by dephosphorylating Rap1 to stabilize the MIT complex. As a consequence, loss of Ptsn ameliorates T cell-mediated colitis. |
