RhoGDI2 positively regulates the Rho GTPases activation in response to the β2 outside-in signaling in T cells adhesion and migration on ICAM-1

Abstract

Cytoskeletal reorganization driven by Rho GTPases plays a crucial role in the migration of T cells, which are key regulators of immunity. The molecular mechanisms that control actin cytoskeleton remodeling during T cell movement have only partially been clarified as the function of many modulators has not been evaluated in these cells. Here, we report a new function of RhoGDI2 by showing that this protein positively regulates Rho GTPase activation during T cell adhesion and migration. RhoGDI2 knockdown significantly reduced T cell adhesion and migration. Furthermore, RhoGDI2 knockdown decreased the activation of Rac1 and Cdc42, 2 members of Rho GTPases, and the remodeling of the actin cytoskeleton. Upon P‐selectin glycoprotein ligand‐1 engagement, RhoGDI2 was phosphorylated at Y24 and Y153 by kinases related to β2 integrin outside‐in signaling, Src, c‐Abl, and Syk, resulting in the accumulation of RhoGDI2 at the cell membrane. Subsequent phosphorylation of S31 induced the opening of RhoGDI2 and the release of Rho GTPases, whereas phosphorylation of Y153 might promote the activation of Rho GTPases by recruiting Vav1. Moreover, the disruption of lipid rafts with methyl‐β‐cyclodextrin blocked the interaction between integrins and RhoGDI2, reducing the level of phosphorylated RhoGDI2 and the activation of downstream Rho GTPases. Based on these observations, RhoGDI2 is a target of intergrin outside‐in signaling that activates Rho GTPases during T cell adhesion and migration, and RhoGDI2‐mediated signal transduction is based on the lipid rafts integrity.

Rho GDP-Dissociation Inhibitor 2 Inhibits C-X-C Chemokine Receptor Type 4-Mediated Acute Lymphoblastic Leukemia Cell Migration

“…Phosphorylation decreases the amount of Rac1 in RhoGDI2 complexes and increases RhoGDI2 association with cell membranes ( 22 ). Although it has been reported that RhoGDI2 positively regulates the activation of Rac1 and Cdc42 ( 20 ), we find the phosphorylation on 24 and 153 tyrosine complex less RhoA or RhoC in human T-ALL cell lines ( Figure 3 ), raising a possibility to release the negative regulatory role of RhoGDI2 in T-ALL cell migration toward CXCL12 ( Figure 4 ).…”

“…RhoGDI2 is reported to negatively or positively regulate RhoGTPases ( 20 ). We previously demonstrated that RhoA and RhoC were required for JURKAT migration toward CXCL12 ( 21 ).…”

“…Recent reports show that RhoGDI2 participates in β1 inside-out signaling ( 16 ) and β2 outside-in signaling ( 20 ) in T lymphocytes. Phosphorylations of p85-bound RhoGDI2 on Y130 and Y153 by c-Abl and Src are required for the complex to be recruited to PSGL1 and thereby regulates β1 integrin-mediated T cell adhesion to VCAM-1 ( 16 ).…”

“…Phosphorylations of p85-bound RhoGDI2 on Y130 and Y153 by c-Abl and Src are required for the complex to be recruited to PSGL1 and thereby regulates β1 integrin-mediated T cell adhesion to VCAM-1 ( 16 ). Upon P-selectin glycoprotein ligand-1 engagement, RhoGDI2 is phosphorylated at Y24 and Y153 by Src, ABL1, and Syk ( 20 ). In bladder cancer, it was demonstrated that, except Y153, Y24 was also the primary Src phosphorylation site ( 22 ).…”

Integrin‐associated molecules and signalling cross talking in osteoclast cytoskeleton regulation

“…Syk is required for β2 integrin conducted cellular spreading and the activation of ERK signalling in myeloid cells including osteoclast . Syk, as a non‐receptor tyrosine kinase, is essential to immune system and associated with various functions of the immune cells.…”