Role of the GNOM gene in Arabidopsis apical-basal patterning--From mutant phenotype to cellular mechanism of protein action.
How the apical-basal axis of polarity is established in embryogenesis is still a mystery in plant development. This axis appeared specifically compromised by mutations in the Arabidopsis GNOM gene. Surprisingly, GNOM encodes an ARF guanine-nucleotide exchange factor (ARF-GEF) that regulates the formation of vesicles in membrane trafficking. In-depth functional analysis of GNOM and its closest relative, GNOM-LIKE 1 (GNL1), has provided a mechanistic explanation for the development-specific role of a seemingly mundane trafficking regulator. The current model proposes that GNOM is specifically involved in the endosomal recycling of the auxin-efflux carrier PIN1 to the basal plasma membrane in provascular cells, which in turn is required for the accumulation of the plant hormone auxin at the future root pole through polar auxin transport. Thus, the analysis of GNOM highlights the importance of cell-biological processes for a mechanistic understanding of development.
Richter
Sandra
S
Center for Plant Molecular Biology - Developmental Genetics, University of Tübingen, Auf der Morgenstelle 3, D-72076 Tübingen, Germany.
Anders
Nadine
N
Wolters
Hanno
H
Beckmann
Hauke
H
Thomann
Alexis
A
Heinrich
Ralph
R
Schrader
Jarmo
J
Singh
Manoj K
MK
Geldner
Niko
N
Mayer
Ulrike
U
Jürgens
Gerd
G
D000818:Animals; D017360:Arabidopsis / Q000196:embryology / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D020662:Guanine Nucleotide Exchange Factors / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D009024:Morphogenesis / Q000502:physiology*; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny
D029681:Arabidopsis Proteins; C088087:GNOM protein, Arabidopsis; D020662:Guanine Nucleotide Exchange Factors