αPIX Rho GTPase Guanine Nucleotide Exchange Factor Regulates Lymphocyte Functions and Antigen Receptor Signaling

Missy, Karine; Hu, Bin; Schilling, Kerstin; Harenberg, Anke; Sakk, Vadim; Kuchenbecker, Kerstin; Kutsche, Kerstin; Fischer, Klaus–Dieter

doi:10.1128/mcb.00507-07

Cited by 42 publications

(58 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We previously reported that aPix 2 mice on a mixed C57BL/6 and 129Sv background have normal numbers of thymocytes, including CD4 + CD8 + DP thymocytes and CD4 + or CD8 + SP subsets, and reduced numbers of peripheral T cells (12). However, defects affecting thymocyte development are often masked by redundant homeostatic mechanisms to ensure sufficient numbers of thymocytes and T cells (1).…”

Section: Impaired Positive Selection In Tcr-transgenic Apix -Micementioning

confidence: 99%

“…In transwell migration assays, aPix 2 T and B cells show increased chemokinesis and increased chemotaxis (12). To determine whether aPix 2 thymocytes also show increased migration in vitro, we measured the transwell migration of all thymocyte subsets (DN, DP, CD4 + SP, and CD8 + SP) to CXCL12 (also known as SDF-1) and CCL25 (also known as TECK).…”

Section: Increased Migration Of Apix -Thymocytes On 2d Surfacesmentioning

confidence: 99%

“…For transwell migration assays, 5-mm-pore membranes (Corning Costar) were coated with 3 mg/ml recombinant mouse ICAM-1/human Fc chimera (R&D Systems) plus anti-CD3 (2C11) where indicated and blocked with 2% BSA. Migration of cells to CXCL12 (200 ng/ml) or CCL25 (100 ng/ ml) was analyzed as described (12).…”

Section: Flow Cytometrymentioning

confidence: 99%

“…For conjugate formation of thymocytes and B cells, CD43 2 B cells were purified on an autoMACS Pro (Miltenyi Biotec), and pulsed overnight with 10 mg/ml OVA peptide (JPT Peptide Technologies) in the presence of 30 mg/ml LPS (Sigma-Aldrich). B cells were mixed at a 1:1 ratio with OT-II + thymocytes and analyzed for conjugate formation by FACS of CD8 + B220 + cell doublets (.95% of CD8 + cells in the thymus are DP thymocytes) as described (12). For transwell migration assays, 5-mm-pore membranes (Corning Costar) were coated with 3 mg/ml recombinant mouse ICAM-1/human Fc chimera (R&D Systems) plus anti-CD3 (2C11) where indicated and blocked with 2% BSA.…”

Section: Flow Cytometrymentioning

confidence: 99%

“…Thus, PIX proteins relay signals from receptors through GTPases to the actin cytoskeleton and act as scaffold proteins for additional signaling intermediates. We previously reported that aPix 2 mice have reduced numbers of peripheral T and B cells, and aPix 2 T cells show greatly increased rates of basal and CXCL12-induced migration (12). Although aPIX and bPIX have both been implicated in cytoskeletal dynamics such as migration, focal adhesion, and polarization in other cell types (12)(13)(14)(15), the role of PIX proteins in thymocyte development and functions is unknown.…”

mentioning

confidence: 99%

See 4 more Smart Citations

αPIX RhoGEF Supports Positive Selection by Restraining Migration and Promoting Arrest of Thymocytes

Korthals

Schilling

Reichardt

et al. 2014

The Journal of Immunology

Self Cite

View full text Add to dashboard Cite

Thymocytes mature in a series of stages by migrating through specific areas of the thymus and interacting with other cells to receive the necessary developmental signals; however, little is known about the molecular mechanisms governing this migration. We report that murine thymocytes with a knockout mutation in α-PAK (p21-activated kinase)-interacting exchange factor (PIX; Arhgef6), an activator of Rho GTPases, showed greatly increased motility and altered morphology in two-dimensional migration on ICAM-1. αPIX was also required for efficient positive selection, but not negative selection, of thymocytes. TCR signaling was normal in αPix− thymocytes, indicating that the effects of αPIX on positive selection are largely independent of TCR signaling. αPix− thymocytes also paused less during migration in the thymic cortex, interacted less with ICAM-1 coated beads, and could overcome TCR stop signals, consistent with defective scanning behavior. These results identify αPIX as a regulator of thymocyte migration and subsequent arrest that is linked to positive selection.

show abstract

Section: Impaired Positive Selection In Tcr-transgenic Apix -Micementioning

confidence: 99%

Section: Increased Migration Of Apix -Thymocytes On 2d Surfacesmentioning

confidence: 99%

Section: Flow Cytometrymentioning

confidence: 99%

Section: Flow Cytometrymentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

αPIX RhoGEF Supports Positive Selection by Restraining Migration and Promoting Arrest of Thymocytes

Korthals

Schilling

Reichardt

et al. 2014

The Journal of Immunology

Self Cite

View full text Add to dashboard Cite

show abstract

Arhgef6 (alpha-PIX) cytoskeletal regulator signals to GTPases and Cofilin to couple T cell migration speed and persistence

Mamula

Korthals

Hradsky

et al. 2021

Journal of Leukocyte Biology

View full text Add to dashboard Cite

Immunity is governed by successful T cell migration, optimized to enable a T cell to fully scan its environment without wasted movement by balancing speed and turning. Here we report that the Arhgef6 RhoGEF (aka alpha-PIX; PIX; Cool-2), an activator of small GTPases, is required to restrain cell migration speed and cell turning during spontaneous migration on 2D surfaces. In Arhgef6 −/− T cells, expression of Arhgef7 (beta-PIX; PIX; Cool-1), a homolog of Arhgef6, was increased and correlated with defective activation and localization of Rac1 and CDC42 GTPases, respectively. Downstream of Arhgef6, PAK2 (p21-activated kinase 2) and LIMK1 phosphorylation was reduced, leading to increased activation of Cofilin, the actin-severing factor. Consistent with defects in these signaling pathways, Arhgef6 −/− T cells displayed abnormal bilobed lamellipodia and migrated faster, turned more, and arrested less than wild-type (WT) T cells. Using pharmacologic inhibition of LIMK1 (LIM domain kinase 1) to induce Cofilin activation in WT T cells, we observed increased migration speed but not increased cell turning. In contrast, inhibition of Cdc42 increased cell turning but not speed. These results suggested that the increased speed of the Arhgef6 −/− T cells is due to hyperactive Cofilin while the increased turning may be due to abnormal GTPase activation and recruitment. Together, these findings reveal that Arhgef6 acts as a repressor of T cell speed and turning by limiting actin polymerization and lamellipodia formation.

show abstract

GIT2—A keystone in ageing and age-related disease

Gastel

Boddaert²,

Jushaj

et al. 2018

Ageing Research Reviews

View full text Add to dashboard Cite

Since its discovery, G protein-coupled receptor kinase-interacting protein 2, GIT2, and its family member, GIT1, have received considerable interest concerning their potential key roles in regulating multiple inter-connected physiological and pathophysiological processes. GIT2 was first identified as a multifunctional protein that is recruited to G protein-coupled receptors (GPCRs) during the process of receptor internalization. Recent findings have demonstrated that perhaps one of the most important effects of GIT2 in physiology concerns its role in controlling multiple aspects of the complex ageing process. Ageing can be considered the most prevalent pathophysiological condition in humans, affecting all tissue systems and acting as a driving force for many common and intractable disorders. The ageing process involves a complex interplay among various deleterious activities that profoundly disrupt the body's ability to cope with damage, thus increasing susceptibility to pathophysiologies such as neurodegeneration, central obesity, osteoporosis, type 2 diabetes mellitus and atherosclerosis. The biological systems that control ageing appear to function as a series of interconnected complex networks. The inter-communication among multiple lower-complexity signaling systems within the global ageing networks is likely coordinated internally by keystones or hubs, which regulate responses to dynamic molecular events through protein-protein interactions with multiple distinct partners. Multiple lines of research have suggested that GIT2 may act as one of these network coordinators in the ageing process. Identifying and targeting keystones, such as GIT2, is thus an important approach in our understanding of, and eventual ability to, medically ameliorate or interdict age-related progressive cellular and tissue damage.

show abstract

αPIX Rho GTPase Guanine Nucleotide Exchange Factor Regulates Lymphocyte Functions and Antigen Receptor Signaling

Cited by 42 publications

References 64 publications

αPIX RhoGEF Supports Positive Selection by Restraining Migration and Promoting Arrest of Thymocytes

αPIX RhoGEF Supports Positive Selection by Restraining Migration and Promoting Arrest of Thymocytes

Arhgef6 (alpha-PIX) cytoskeletal regulator signals to GTPases and Cofilin to couple T cell migration speed and persistence

GIT2—A keystone in ageing and age-related disease

Contact Info

Product

Resources

About