| NSF Org: |
MCB Division of Molecular and Cellular Biosciences |
| Recipient: |
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| Initial Amendment Date: | March 22, 2010 |
| Latest Amendment Date: | January 31, 2012 |
| Award Number: | 0948584 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Gregory W. Warr
MCB Division of Molecular and Cellular Biosciences BIO Directorate for Biological Sciences |
| Start Date: | April 1, 2010 |
| End Date: | March 31, 2014 (Estimated) |
| Total Intended Award Amount: | $679,091.00 |
| Total Awarded Amount to Date: | $679,091.00 |
| Funds Obligated to Date: |
FY 2011 = $224,265.00 FY 2012 = $237,912.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
426 AUDITORIUM RD RM 2 EAST LANSING MI US 48824-2600 (517)355-5040 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
426 AUDITORIUM RD RM 2 EAST LANSING MI US 48824-2600 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Cellular Dynamics and Function |
| Primary Program Source: |
01001213DB NSF RESEARCH & RELATED ACTIVIT 01001011DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.074 |
ABSTRACT
Intellectual merit. It is well established that cells of plants, fungi, and animals contain organelles that carry out vital functions for the life of a cell. What is yet to be learned is how the identity of organelles is established and maintained. In this project, the plant Golgi apparatus will be used as a model to address this fundamental question. In plants, the Golgi apparatus is composed of highly mobile stacks of membranes that are dispersed on tubules of another organelle, the endoplasmic reticulum. The plant Golgi receives proteins and membranes from proximal and distal locations; it is involved in their modification and sorting to their final destinations and in synthesizing the cell wall that encapsulates plant cells. The flow of membrane proteins through the Golgi as well as the dynamic exchange of peripherally associated proteins require continuous remodeling of this organelle. Yet, the stacks withstand dispersion during the intense traffic of proteins and membranes to and from the Golgi. This raises the fundamental biological question: How does the Golgi retain its integrity (i.e. architecture and composition) The integrity of the Golgi depends on the organelle's ability to dynamically maintain its steady-state architecture and membrane distribution during protein traffic. Using a screen specifically developed for the plant Golgi in the Brandizzi laboratory, a unique set of mutants was identified in which an established Golgi marker is partially mistargeted to other organelles. This screen is exciting and important because it sets the foundation for identifying key players of the machinery that controls plant Golgi integrity. In this project, characterization of the Golgi mutants will be carried out to identify the protein(s) responsible for the maintenance of the architecture and membrane steady-state distribution at the plant Golgi. This work will lead to answers to fundamental questions regarding organelle biogenesis and important differences in Golgi organization and function across eukaryotic biological systems.
Broader impacts. Plants are the primary energy source of all biospheric development all animals survive on plants, both directly and indirectly. The secretory pathway of plants plays a fundamental role in the conversion of fixed carbon into energy-rich materials such as proteins, lipids, and complex sugars. These plant-derived products are important not only for nutrition, but they have the potential to be used as renewable fuels, lubricants, textiles, and building materials of all kinds. The plant Golgi is a key organelle in cell wall biosynthesis and storage protein deposition. Because unique variations exist among systems as a result of evolutionary adaptation, it is important to study the plant Golgi if humanity is to tap into the full potential of plants as primary providers of biomolecules on earth. This project will also enable to continue the Brandizzi lab's engagement in teaching and outreach activities to communicate to students and teachers the scientific discoveries in plant science and their impact on our society.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Intellectual merit: Research in our award focused on understanding how the Golgi apparatus of plants establishes and maintains its identity, despite intense traffic of proteins and continuous remodeling of membranes. Our research not only aimed to provide fascinating insights into one of the most complex transport systems of plant cells, it also addressed fundamental questions of how organelles maintain a functional compartmentalization that is essential for the life of the cell. To harness the unique features of the organization of the plant Golgi and to identify key genes controlling the integrity of this organelle, we invested considerable resources to carry out forward genetics screens of the Golgi. This kind of screen takes advantage of ethyl methanesulfonate (EMS) mutagenesis, which is useful for the isolation of novel sub-lethal alleles with loss and gain of function phenotypes. Our confocal microscopy-based screen detected morphological and functional defects of the Golgi compared to wild type through the analysis of the subcellular distribution of a specific organelle marker via live cell imaging of Arabidopsis leaf epidermal cells. Specifically, the aim of our award was to characterize Arabidopsis mutants expressing the Golgi marker, ST-GFP (cytosolic tail and transmembrane domain of a rat sialyl-transferase fused to GFP) that have defects in Golgi organization and function visualized by an aberrant subcellular distribution of ST-GFP compared to wild type. The screen has been successful, thanks to our long-term expertise in the study of the plant secretory pathway coupled with excellent collaborations and an innovative mutant mapping approach setup in our lab. During our award, we have made important contributions to the eukaryotic cell community by identifying key proteins that control the functional and morphological integrity of the plant Golgi in relation to other organelles, especially the endoplasmic reticulum (ER). Numerous manuscripts including research and review articles in peer-reviewed journals that cite our NSF award specifically support evidence this fact. We have isolated and characterized mutants with defects in ER-Golgi protein traffic due to novel mutations in the ER export machinery, as well mutants with defects on the known as well novel regulators of the Golgi function and dynamic integrity, and mutants with defects in the positioning and movement of the Golgi apparatus. Our findings have opened new paradigms in the biology of the plant Golgi by providing evidence for a regulation of Golgi integrity and function depend on developmental stages of the cell as well from proteins that are not associated with the Golgi membranes. Our findings have also opened new areas of research that are currently pursued in our lab with support from NSF MCB.
Broader impact: We have enhanced educational infrastructure at the university by including our research findings in teaching and outreach activities in which the PI is involved, including (i) the MSU Frontiers in Science Weekend Workshop Series in which science teachers follow lectures on cutting-edge scientific developments and visit science labs to take back to the classroom new developments in science, and (ii) Eukaryotic Cell Biology undergraduate course (MMG 409), co-taught by this PI. We also participated in the High School Honors Science/ Mathematics/ Engineering Program (HSHSP), sponsored by the MSU Department of Teacher Education to provide high school students the opportunity to conduct full-time research in the summer. NSF MCB support has also enabled us to train a number of enthusiastic and energetic researchers. Specifically, we have trained post-doc associates, graduate students, undergraduate students, Research Experiences for Undergraduates students, and high-school teachers. Besides disseminating our findings in peer-reviewed pu...
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