It has become increasingly clear that eukaryotic cells have highly dynamic organelles. The four exciting sessions in the 2012 annual meeting’s organelle dynamics theme will highlight state-of-the-art approaches aimed at understanding how the dynamic behavior of organelles is linked to their functions. These sessions will focus on mitochondrial dynamics, organelle quality control, the organization of the secretory pathway and endomembrane system dynamics.
The first session will feature the mitochondrion as an organelle whose dynamic properties are central for its function. Jodi Nunnari (University of California, Davis) will discuss how the fusion and fission of mitochondria are regulated. Her group has developed in vitro assays that allow for the identification of regulatory factors.
David Chan (California Institute of Technology) is examining how the dynamic behavior of mitochondria regulates their function. Dysfunction of mitochondrial dynamics is associated with neurodegenerative disease. His group has developed mouse models to investigate the link between mitochondrial dynamics and cell physiology.
Hiromi Sesaki (Johns Hopkins University School of Medicine) will discuss the molecular mechanisms and physiological functions of mitochondrial fusion and fission.
Organelle quality control
The second session will focus on how cells ensure organellar integrity. Tamotsu Yoshimori (Osaka University) will discuss the longstanding debate concerning the origin of autophagosomes, which are unique, ad hoc organelles that form transiently. Recent results indicate the endoplasmic reticulum and mitochondria are involved in autophagosome biogenesis. Yoshimori also will describe how autophagosomes form to combat intracellular bacteria.
Thomas Langer (University of Cologne) is exploring how mitochondrial proteases control mitochondrial dynamics. The processing and stability of the dynamin-like GTPase OPA1 is emerging as a central mechanism to monitor mitochondrial integrity. Using yeast and mice as model systems, Langer’s group examines the relevance of stress-induced degradation of OPA1 for mitochondrial quality control and neuronal survival.
Finally, Gia Voeltz (University of Colorado-Boulder) will describe the mechanisms that regulate the three-dimensional structure of the endoplasmic reticulum. Her talk will focus on how three main factors – membrane shaping proteins, cytoskeletal dynamics and interactions with other organelles – work together to distribute the endoplasmic reticulum throughout the cytoplasm and generate the complexity of ER functional domains.
Organization of the secretory pathway
The third session will focus on how compartments of the secretory pathway are generated and maintained. Ben Glick (University of Chicago) will describe how the ER export domains known as transitional ER sites are established within the rough ER. Transitional ER sites are defined by a dynamic balance between growth and export-mediated shrinkage. His group is studying how a protein called Sec16 controls tER dynamics by regulating ER export.
Nava Segev (University of Illinois at Chicago) studies molecular switches and cascades regulating protein traffic in yeast. She focuses on the roles and interactions of small GTPases of the conserved Ypt/Rab family, which regulates multiple steps of transport in the secretory and endocytic pathways. Her group is investigating how various Ypt/Rab GTPases cooperate to specify compartment identity and turnover.
Adam Linstedt (Carnegie Mellon University) studies the mammalian secretory pathway with an emphasis on the Golgi apparatus. His work includes structure-function studies of tethering proteins, which have multiple roles in the capture of transport vesicles and the establishment of Golgi structure.
Endomembrane system dynamics
The fourth session will focus on how compartments of the secretory and endocytic pathways communicate and change over time. Christian Ungermann (University of Osnabrück in Germany) studies membrane dynamics of endosomes and lysosomes (or vacuoles in yeast). He will describe how Rab GTPases work together with large tethering complexes to regulate membrane fusion and endosome maturation.
Jon Audhya (University of Wisconsin, Madison) will describe the development of C. elegans as a model system to study how membrane trafficking and organelle dynamics are modulated during development, cell proliferation and cell differentiation. His lab studies the ESCRT complex, which promotes membrane fission reactions at late endosomes and other cellular locations.
Catherine Rabouille (Hubrecht Institute) will describe how her group has developed Drosophila as a powerful model system for studying the cell biology of the secretory pathway. Her work includes studies of ER export and Golgi organization as well as unconventional secretion mechanisms that bypass the traditional secretory pathway.
Ben Glick (firstname.lastname@example.org) is a professor at the University of Chicago, and David Chan (email@example.com) is an associate professor and Howard Hughes Medical Institute investigator at the California Institute of Technology.