UNASSIGNED: Rhos of plants (ROPs) play a key role in plant cell morphogenesis, especially in tip-growing pollen tubes and root hairs, by regulating an array of intracellular activities such as dynamic polymerization of actin microfilaments. ROPs are regulated by @entity6370 exchange factors (RopGEFs), GTPase activating proteins (RopGAPs), and @entity6370 dissociation inhibitors (RhoGDIs). RopGEFs and RopGAPs play evolutionarily conserved function in @entity6109 signaling. By contrast, although plant RhoGDIs regulate the membrane extraction and cytoplasmic sequestration of ROPs, less clear are their positive roles in @entity6109 signaling as do their @entity375 and metazoan counterparts. We report here that functional loss of all three @entity958 ( @entity958 ) GDIs (tri-gdi) significantly reduced male transmission due to impaired pollen tube growth in vitro and in vivo. We demonstrate that ROPs were ectopically activated at the lateral plasma membrane of the tri-gdi pollen tubes. However, total ROPs were reduced posttranslationally in the tri-gdi mutant, resulting in overall dampened @entity6109 signaling. Indeed, a @entity69362 mutant that was unable to interact with GDIs failed to induce growth, indicating the importance of the @entity6109 -GDI interaction for @entity6109 signaling. Functional loss of @entity73 cellular homeostasis, resulting in excess apical accumulation of wall components in pollen tubes, similar to that resulting from ectopic @entity1078 signaling. GDIs and @entity1078 may antagonistically coordinate to maintain cellular homeostasis during pollen tube growth. Our results thus demonstrate a more complex role of GDIs in @entity6109 -mediated pollen tube growth.

XXXX RhoGDIs Are Critical for Cellular Homeostasis of Pollen Tubes.

@entity69362 :: ('829750(Tax:3702)', 'Gene') :: ['ROP5'] @entity6370 :: ('CHEBI:61292', 'Chemical') :: ['guanine nucleotide'] @entity1078 :: ('CHEBI:18348', 'Chemical') :: ['phosphatidylinositol 4,5-bisphosphate'] @entity958 :: ('3702', 'Species') :: ['Arabidopsis thaliana', 'Arabidopsis'] @entity73 :: ('MESH:D003072', 'Disease') :: ['GDIs impaired'] @entity6109 :: ('MESH:C536382', 'Disease') :: ['ROP'] @entity375 :: ('4932', 'Species') :: ['yeast']
@entity958 :: (3702,Species) :: ['Arabidopsis']
