Endosome dynamics regulated by a Rho protein

Abstract

Vesicular transport is a dynamic process that requires coordinated interactions between membrane and cytoskeleton. The mechanisms and molecules integrating these interactions are unclear. A Rho protein, RhoD, might provide a molecular link between membrane traffic and the cytoskeleton. Activated RhoD causes rearrangements of the actin cytoskeleton and cell surface, and governs early endosome motility and distribution.

Novel small GTPase M-Ras participates in reorganization of actin cytoskeleton

“…To determine the entire coding sequence of gMt1, we screened a C2 myotube cDNA library with the PCR product and obtained six positive clones (gMt1a ± f). Among them, gMt1e included an entire coding sequence, which was identical to recently reported RhoD (Murphy et al, 1996). gMt1d contained another sequence coding for a novel small GTPase.…”

“…Thus, it is necessary to investigate the roles of M-Ras and RhoD, in addition to the other Ras and Rho family proteins, in the above cellular events during myogenesis. Particularly, since M-Ras, Cdc42, Rac1 and RhoD are likely to mediate reorganization and disappearance of the stress ®bers (Kozma et al, 1995;Murphy et al, 1996;Manser et al, 1997) (data not shown), they may hinder the development of the structurally related myo®lament bundles. Alternatively, because the stress ®bers are replaced by the myo®lament bundles during myo®brillogenesis, disassembly of the stress ®bers by these small GTPases may be a prerequisite for the formation of myo®lament bundles.…”

“…Among them, one clone encoded recently reported RhoD (Murphy et al, 1996). Another clone coded for a novel member of Ras family, and thus the protein was designated as M-Ras.…”

Farnesylcysteine analogues inhibit store-regulated Ca2+ entry in human platelets: evidence for involvement of small GTP-binding proteins and actin cytoskeleton

“…In contrast, the physical trafficking of endoplasmic reticulum towards the plasma membrane is another mechanism to be considered [3]. Recently, Rho D has been proposed as a candidate for a molecule that co-ordinates vesicle transport with the rearrangement of the actin cytoskeleton [64]. (3) The control of actin reorganization by Ras proteins [16,17,30,31] could participate in the maintenance of a cytoskeletal structure supporting a direct coupling between the intracellular stores and the plasma membrane.…”

Regulation of endocytic traffic by Rho GTPases

“…The RhoD GTPase is present at the plasma membrane and on early endocytic vesicles [70]. Expression of constitutively active RhoD causes alignment of these vesicles with actin filaments and a loss of early endocytic motility [70,71].…”