Novel Role of Ras-GTPase Activating Protein SH3 Domain-Binding Protein G3BP in Adhesion and Migration of 32D Myeloid Progenitor Cells

Abstract

Rho GTPases are involved in homing and mobilization of hematopoietic stem and progenitor cells due to their impact on cytoskeleton remodeling. We have previously shown that inhibition of Rho, Rac and Cdc42 clearly impairs adhesion of normal and leukemic hematopoietic progenitor cells (HPC) to fibronectin and migration in a three-dimensional stromal cell model. Here, we identified the Ras GTPase-Activating Protein SH3 Domain-Binding Protein (G3BP) as a target gene of Rho GTPases and analysed its role in regulating HPC motility. Overexpression of G3BP significantly enhanced adhesion of murine 32D HPC to fibronectin and human umbilical vein endothelial cells, increased the proportion of adherent cells in a flow chamber assay and promoted cell migration in a transwell assay and a three-dimensional stromal cell model suggesting a strong impact on the cytoskeleton. Immunofluorescent staining of G3BP-overexpressing fibroblasts revealed a Rho-like phenotype characterized by formation of actin stress fibers in contrast to the Rac-like phenotype of control fibroblasts. This is the first report implicating a role for G3BP in Rho GTPase-mediated signalling towards adhesion and migration of HPC. Our results may be of clinical importance, since G3BP was found overexpressed in human cancers.

Phosphoproteome Profiling of SH-SY5y Neuroblastoma Cells Treated with Anesthetics: Sevoflurane and Isoflurane Affect the Phosphorylation of Proteins Involved in Cytoskeletal Regulation

“…The Rho GTPase has recently been found to be implicated in the plasticity of dendritic spines in the adult brain as well [ 23 ]. Another protein that was phosphorylated in sevoflurane-treated cells and considered a related marker for cytoskeletal dynamics is the Ras-GAP SH3 binding protein, which has been shown to interact with RasGAP via its SH3 domain and to play a role in cell migration and adhesion [ 24 , 25 ]. Finally, proteins that act as key regulators of cytoskeletal dynamics include the Rho GTPase activating protein, actin-related protein, and actin.…”