Arabidopsis RabF1 (ARA6) Is Involved in Salt Stress and Dark-Induced Senescence (DIS).

Congfei Yin,Hongsheng Zhang,Henrik Aronsson,Sazzad Karim

doi:10.3390/ijms18020309

Congfei Yin, Hongsheng Zhang + Show 2 more

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https://doi.org/10.3390/ijms18020309

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Abstract

Arabidopsis small GTPase RabF1 (ARA6) functions in endosomal vesicle transport and may play a crucial role in recycling and degradation of molecules, thus involved in stress responses. Here we have reported that complementary overexpression lines RabF1OE (overexpression), GTPase mutants RabF1Q93L (constitutively active) and RabF1S47N (dominant negative) lines show longer root growth than wild-type, rabF1 knockout and N-myristoylation deletion (Δ1−29, N-terminus) complementary overexpression mutant plants under salt induced stress, which indicates that N-myristoylation of RabF1 is indispensable for salt tolerance. Moreover, RabF1 is highly expressed during senescence and RabF1OE lines were more tolerant of dark-induced senescence (DIS) than wild-type and rabF1.

Highlights

Small GTPase Rab proteins are mainly involved in membrane transport between organelles, through vesicle transport of cargo proteins to their destinations
According to the Arabidopsis eFP Browser, RabF1 responds to osmotic stress, and recently, it was reported that RabF1Q93L lines were more tolerant to salt stress [11,12]
Salt stress data from overexpression RabF1 lines without the N-myristoylation site strongly indicate that membrane anchoring plays an important role in the increased tolerance to salt stress (Figure 1)

Summary

Introduction

Small GTPase Rab proteins are mainly involved in membrane transport between organelles, through vesicle transport of cargo proteins to their destinations. Rab proteins interact with other regulatory and effector proteins to regulate the cycle of GDP/GTP binding and GTP hydrolysis They have regulatory roles in vesicle budding from the donor membrane followed by uncoating, movement through the cell, tethering and docking in the vicinity of the acceptor membrane and final delivery of cargo to the target membrane by membrane fusion, as well as cargo sorting during coated vesicle transport [3,4,5,6]. RabF1 characterizes by its association to the membranes with its unique N-terminal myristoylation site, rather than the common but essential carboxy-terminal geranylgeranylation CC motif for all other Rab proteins to be prenylated (membrane association) [4,9]

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