Rac1, a member of the Rho family of small GTPases, has been shown to promote formation of lamellipodia at the leading edge of motile cells and affect cell migration. We previously demonstrated that calmodulin can bind to a region in the C-terminal of Rac1 and that this interaction is important in the activation of platelet Rac1. Now, we have analyzed amino acid residue(s) in the Rac1-calmodulin...

BACKGROUND Polycystic ovarian syndrome (PCOS) is characterized by the presence of multiple follicular cysts, giving rise to infertility due to anovulation. This syndrome affects about 10% of women, worldwide. The exact molecular mechanism leading to PCOS remains obscure. RhoGTPase has been associated with oogenesis, but its role in PCOS remains unexplored. Therefore, we attempted to elucidate t...

In skeletal muscle, the actin cytoskeleton-regulating GTPase, Rac1, is necessary for insulin-dependent GLUT4 translocation. Muscle contraction increases glucose transport and represents an alternative signaling pathway to insulin. Whether Rac1 is activated by muscle contraction and regulates contraction-induced glucose uptake is unknown. Therefore, we studied the effects of in vivo exercise and...

Thiopurine drugs are widely used as antileukemic drugs and immunosuppressive agents, and 6-thioguanosine triphosphate ((S)GTP) is a major metabolite for these drugs. Recent studies have suggested that thiopurine drugs may exert their cytotoxic effects partly through binding of (S)GTP to a GTP-binding protein, Rac1. However, it remains unclear whether (S)GTP can also bind to other cellular prote...

McDonald P, Veluthakal R, Kaur H, Kowluru A. Biologically active lipids promote trafficking and membrane association of Rac1 in insulin-secreting INS 832/13 cells. Am J Physiol Cell Physiol 292: C1216 –C1220, 2007. First published October 11, 2006; doi:10.1152/ajpcell.00467.2006.—Despite emerging evidence to suggest that glucose-stimulated insulin secretion (GSIS) requires membrane targeting of...

BACKGROUND Rac1 is a Rho-family small GTP-ase, when activated is pivotal in NAD(P)H oxidase (NOX) activation and generation of reactive oxygen species (ROS). Evidence links Rac1 activation to receptor-mediated albumin endocytosis in the proximal tubule cell (PTC). Thus in states of albumin overload, Rac1 activation could lead to NOX activation and ROS formation in the PTC. Furthermore, accumula...

Rac1 is a &Rgr;-family GTP-binding protein that controls lamellipodia formation and membrane ruffling in fibroblasts. Recently, Rac1 and Cdc42, another member of the &Rgr;-family, have been shown to regulate Fc receptor-mediated phagocytosis in macrophages by controlling different steps of membrane and actin dynamics leading to particle engulfment. Here, we investigated the function of Rac1 usi...

Both cell adhesion protein CD44 and its main ligand hyaluronic acid (HA) are thought to be involved in several processes ultimately requiring cytoskeleton rearrangements. Here, we show that the small guanine nucleotide (GTP)-binding protein, Rac1, can be activated upon HA binding to CD44. When applied locally to a passive cell edge, HA promoted the formation of lamellipodial protrusions in the ...

We have transiently expressed a dominant negative form of rac1 (N17rac1) using adenoviral-mediated gene transfer. The level of N17rac1 expression is demonstrated to be proportional to the multiplicity of infection. Expression of N17rac1 in Rat 2 fibroblasts results in cytostatic growth arrest. Cell-cycle analysis demonstrates that cells expressing N17rac1 accumulate in G2/M. These results sugge...