scholarly journals Rabs, Rips, FIPs, and Endocytic Membrane Traffic

2003 ◽  
Vol 3 ◽  
pp. 870-880 ◽  
Author(s):  
Rytis Prekeris

Rab GTPases, proteins belonging to the Ras-like small GTP-binding protein superfamily, have emerged as master regulators of cellular membrane transport. Rab11 GTPase, a member of the Rab protein family, plays a role in regulating various cellular functions, including plasma membrane recycling, phagocytosis, and cytokinesis. Rab11 acts by forming mutually exclusive complexes with Rab11-family binding proteins, known as FIPs. Rab11-FIP complexes serve a role of �targeting complexes� by recruiting various membrane traffic factors to cellular membranes. Recent studies have identified several Rab11-FIP complex-binding proteins that regulate distinct membrane traffic pathways.

2019 ◽  
Vol 78 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Abdul Razaque Memon ◽  
Christiane Katja Schwager ◽  
Karsten Niehaus

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.


2013 ◽  
Vol 394 (8) ◽  
pp. 1077-1090 ◽  
Author(s):  
Kristin Wächter ◽  
Marcel Köhn ◽  
Nadine Stöhr ◽  
Stefan Hüttelmaier

Abstract The IGF2 mRNA-binding protein family (IGF2BPs) directs the cytoplasmic fate of various target mRNAs and controls essential cellular functions. The three IGF2BP paralogues expressed in mammals comprise two RNA-recognition motifs (RRM) as well as four KH domains. How these domains direct IGF2BP paralogue-dependent protein function remains largely elusive. In this study, we analyze the role of KH domains in IGF2BPs by the mutational GXXG-GEEG conversion of single KH domain loops in the context of full-length polypeptides. These analyses reveal that all four KH domains of IGF2BP1 and IGF2BP2 are essentially involved in RNA-binding in vitro and the cellular association with RNA-binding proteins (RBPs). Moreover the KH domains prevent the nuclear accumulation of these two paralogues and facilitate their recruitment to stress granules. The role of KH domains appears less pronounced in IGF2BP3, because GxxG-GEEG conversion in all four KH domains only modestly affects RNA-binding, subcellular localization and RNA-dependent protein association of this paralogue. These findings indicate paralogue-dependent RNA-binding properties of IGF2BPs which likely direct distinct cellular functions. Our findings suggest that IGF2BPs contact target RNAs via all four KH domains. This implies significant structural constraints, which presumably allow the formation of exceedingly stable protein-RNA complexes.


2008 ◽  
Vol 4 (11) ◽  
pp. e1000216 ◽  
Author(s):  
George A. Belov ◽  
Qian Feng ◽  
Krisztina Nikovics ◽  
Catherine L. Jackson ◽  
Ellie Ehrenfeld

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