| Abstract Detail
Protein Targeting and Vesicular Trafficking Thole, Julie [1], Nielsen, Erik [2]. The Emerging Role of Phosphoinositides in Root Hair Development. Polarized growth is a critical process required for the growth and differentiation of plant cells. This process requires precise control of membrane trafficking pathways, which are regulated in part by Rab GTPases. To understand the mechanisms underlying polarized secretion in plants, we have identified a plant Rab GTPase, RabA4b, which localizes to the tips of growing root hairs and is believed to be involved in the trafficking of cell wall material to the tips of these growing cells.
We have identified the phosphoinositide-4OH kinase, PI-4KB1 as a RabA4b effector protein, and plants lacking PI-4KB1 and its homologue PI-4KB2 display aberrant root hair morphology. Analysis of root hair development mutants by time-lapse fluorescence microscopy revealed unique patterns of RabA4b localization. Of particular interest was rhd4-1, which has short, bulged root hairs. During bulge formation in the rhd4-1 root hairs, the RabA4b compartment becomes disorganized, but reorganizes when tip growth reestablished from these bulges. To understand the role of RHD4 in polarized secretion, we utilized a map based cloning strategy and we have identified RHD4 as a phosphoinositide phosphatase. Taken together, these results highlight the importance that regulation of phosphoinositide pools plays during the organization of polarized secretion in root hair cells.
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1 - Washington University in St. Louis, Department of Biology, One Brookings Drive, Campus Box 1137
2 - University of Michigan, Department of Molecular, Cellular, and Developmental Biology
Keywords:
root hair development
phosphoinositide
membrane trafficking
Rab GTPase.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P22021
Abstract ID:1263 |
