scholarly journals Expression of small GTPases in the roots and nodules of Medicago truncatula cv. Jemalong

2019 ◽  
Vol 78 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Abdul Razaque Memon ◽  
Christiane Katja Schwager ◽  
Karsten Niehaus
Keyword(s):  
Medicago Truncatula ◽  
Binding Proteins ◽  
Polymerase Chain Reaction Analysis ◽  
Small Gtpases ◽  
Infection Process ◽  
Nodule Development ◽  
Gtp Binding Proteins ◽  
Gtp Binding ◽  
Differential Expression Pattern

Abstract In this study we used Medicago truncatula, to identify and analyze the expression of small GTP-binding proteins (Arf1, Arl1, Sar1, Rabs, Rop/Rac) and their interacting partners in the infection process in the roots and nodules. A real-time polymerase chain reaction analysis was carried out and our results showed that Arf1 (AtArfB1c-like), MtSar1, AtRabA1e-like, AtRabC1-like, MsRab11-like and AtRop7-like genes were highly expressed in the nodules of rhizobium inoculated plants compared to the non-inoculated ones. On the contrary, AtRabA3 like, AtRab5c and MsRac1-like genes were highly expressed in non-infected nitrogen supplied roots of M. truncatula. Other Rab genes (AtRabA4a, AtRabA4c and AtRabG3a-like genes) were nearly equally expressed in both treatments. Interestingly, RbohB (a respiratory burst NADPH oxidase homologue) was more highly expressed in rhizobium infected than in non-infected roots and nodules. Our data show a differential expression pattern of small GTP-binding proteins in roots and nodules of the plants. This study demonstrates an important role of small GTP-binding proteins in symbiosome biogenesis and root nodule development in legumes.

scholarly journals Actin filament organization in activated mast cells is regulated by heterotrimeric and small GTP-binding proteins.

1994 ◽  
Vol 126 (4) ◽  
pp. 1005-1015 ◽  
Author(s):  
J C Norman ◽  
L S Price ◽  
A J Ridley ◽  
A Hall ◽  
A Koffer
Keyword(s):  
Mast Cells ◽  
Actin Filaments ◽  
Actin Polymerization ◽  
Binding Proteins ◽  
Small Gtpases ◽  
Secretory Cells ◽  
Cortical Region ◽  
Permeabilized Cells ◽  
Gtp Binding Proteins ◽  
Gtp Binding

Rat peritoneal mast cells, both intact and permeabilized, have been used widely as model secretory cells. GTP-binding proteins and calcium play a major role in controlling their secretory response. Here we have examined changes in the organization of actin filaments in intact mast cells after activation by compound 48/80, and in permeabilized cells after direct activation of GTP-binding proteins by GTP-gamma-S. In both cases, a centripetal redistribution of cellular F-actin was observed: the content of F-actin was reduced in the cortical region and increased in the cell interior. The overall F-actin content was increased. Using permeabilized cells, we show that AIF4-, an activator of heterotrimeric G proteins, induces the disassembly of F-actin at the cortex, while the appearance of actin filaments in the interior of the cell is dependent on two small GTPases, rho and rac. Rho was found to be responsible for de novo actin polymerization, presumably from a membrane-bound monomeric pool, while rac was required for an entrapment of the released cortical filaments. Thus, a heterotrimeric G-protein and the small GTPases, rho and rac, participate in affecting the changes in the actin cytoskeleton observed after activation of mast cells.

Cellular responses regulated by rho-related small GTP-binding proteins

1993 ◽  
Vol 340 (1293) ◽  
pp. 267-271 ◽  
Keyword(s):  
Plasma Membrane ◽  
Binding Proteins ◽  
Focal Adhesions ◽  
Receptor Activation ◽  
Small Gtpases ◽  
Membrane Receptors ◽  
Phagocytic Cells ◽  
Gtp Binding Proteins ◽  
Gtp Binding ◽  
Plasma Membrane Receptors

Rho-related proteins are members of the ras superfamily of small GTP-binding proteins. Their function in fibroblasts has been analysed using microinjection of living cells. Rho appears to link plasma membrane receptors to the assembly of focal adhesions and actin stress fibres. The closely related protein rac, on the other hand, links receptors to the polymerization of actin at the plasma membrane to form membrane ruffles and pinocytotic vesicles. In phagocytic cells, rac has been shown to be required for activation of a membrane-bound NADPH oxidase in response to receptor activation. These systems provide the basis for a working model for the mechanism of action of the rho family of small GTPases.

Sign in / Sign up

Export Citation Format

Share Document