First published online June 21, 2005; 10.1105/tpc.105.031112
The Plant Cell 17:2020-2036 (2005)
© 2005 American Society of Plant Biologists
A Rab-E GTPase Mutant Acts Downstream of the Rab-D Subclass in Biosynthetic Membrane Traffic to the Plasma Membrane in Tobacco Leaf Epidermis
Huanquan Zhenga,1,
Luísa Camachob,
Edmund Weea,
Henri Batokoa,2,
Julia Legena,
Christopher J. Leavera,
Rui Malhóc,
Patrick J. Husseyb and
Ian Moorea,3
a Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, United Kingdom
b Integrative Cell Biology Laboratory, School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE, United Kingdom
c Universidade de Lisboa, Faculdade de Ciências de Lisboa, Instituto de Ciencia Aplicada e Tecnologia, 1749-016 Lisboa, Portugal
3 To whom correspondence should be addressed. E-mail ian.moore{at}plants.ox.ac.uk; fax 44-1865-275074.
The function of the Rab-E subclass of plant Rab GTPases in membrane traffic was investigated using a dominant-inhibitory mutant (RAB-E1d[NI]) of Arabidopsis thaliana RAB-E1d and in vivo imaging approaches that have been used to characterize similar mutants in the plant Rab-D2 and Rab-F2 subclasses. RAB-E1d[NI] inhibited the transport of a secreted green fluorescent protein marker, secGFP, but in contrast with dominant-inhibitory RAB-D2 or RAB-F2 mutants, it did not affect the transport of Golgi or vacuolar markers. Quantitative imaging revealed that RAB-E1d[NI] caused less intracellular secGFP accumulation than RAB-D2a[NI], a dominant-inhibitory mutant of a member of the Arabidopsis Rab-D2 subclass. Furthermore, whereas RAB-D2a[NI] caused secGFP to accumulate exclusively in the endoplasmic reticulum, RAB-E1d[NI] caused secGFP to accumulate additionally in the Golgi apparatus and a prevacuolar compartment that could be labeled by FM4-64 and yellow fluorescent protein (YFP)tagged Arabidopsis RAB-F2b. Using the vacuolar protease inhibitor E64-d, it was shown that some secGFP was transported to the vacuole in control cells and in the presence of RAB-E1d[NI]. Consistent with the hypothesis that secGFP carries a weak vacuolar-sorting determinant, it was shown that a secreted form of DsRed reaches the apoplast without appearing in the prevacuolar compartment. When fused to RAB-E1d, YFP was targeted specifically to the Golgi via a saturable nucleotide- and prenylation-dependent mechanism but was never observed on the prevacuolar compartment. We propose that RAB-E1d[NI] inhibits the secretory pathway at or after the Golgi, causing an accumulation of secGFP in the upstream compartments and an increase in the quantity of secGFP that enters the vacuolar pathway.
This article has been cited by other articles:

|
 |

|
 |
 
I. Hwang
Sorting and Anterograde Trafficking at the Golgi Apparatus
Plant Physiology,
October 1, 2008;
148(2):
673 - 683.
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
M. A. Held, A. Boulaflous, and F. Brandizzi
Advances in Fluorescent Protein-Based Imaging for the Analysis of Plant Endomembranes
Plant Physiology,
August 1, 2008;
147(4):
1469 - 1481.
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
E. Nielsen, A. Y. Cheung, and T. Ueda
The Regulatory RAB and ARF GTPases for Vesicular Trafficking
Plant Physiology,
August 1, 2008;
147(4):
1516 - 1526.
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
E. Antony, T. Taybi, M. Courbot, S. T. Mugford, J. A. C. Smith, and A. M. Borland
Cloning, localization and expression analysis of vacuolar sugar transporters in the CAM plant Ananas comosus (pineapple)
J. Exp. Bot.,
May 1, 2008;
59(7):
1895 - 1908.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
R. U. Rehman, E. Stigliano, G. W. Lycett, L. Sticher, F. Sbano, M. Faraco, G. Dalessandro, and G.-P. Di Sansebastiano
Tomato Rab11a Characterization Evidenced a Difference Between SYP121-Dependent and SYP122-Dependent exocytosis
Plant Cell Physiol.,
May 1, 2008;
49(5):
751 - 766.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
C.-M. Chow, H. Neto, C. Foucart, and I. Moore
Rab-A2 and Rab-A3 GTPases Define a trans-Golgi Endosomal Membrane Domain in Arabidopsis That Contributes Substantially to the Cell Plate
PLANT CELL,
January 1, 2008;
20(1):
101 - 123.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
P. R. Hunter, C. P. Craddock, S. Di Benedetto, L. M. Roberts, and L. Frigerio
Fluorescent Reporter Proteins for the Tonoplast and the Vacuolar Lumen Identify a Single Vacuolar Compartment in Arabidopsis Cells
Plant Physiology,
December 1, 2007;
145(4):
1371 - 1382.
[Abstract]
[Full Text]
[PDF]
|
 |
|
|
|