Cell and Development Biology

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Barbara Conradt

Control of apoptosis during animals development

neuroblast-conradtThe elimination of unwanted, superfluous cells by programmed cell death or ’apoptosis’ is important for development and the maintenance of cellular homeostasis in multi-cellular animals. The deregulation of apoptosis in humans can lead to various diseases, such as cancer, autoimmune diseases or neurodegenerative disorders, underscoring the relevance of this process for human health.

NSM neuroblast division: The birth of a cell that
is programmed to die. Real-time in vivo imaging.

CEM-conradtMost of our current knowledge of the apoptotic process is based on genetic and molecular analyses of the nematode C. elegans. These analyses revealed that the central cellular machinery that brings about apoptosis in animals as diverse as C. elegans and humans is conserved. Using C. elegans as a tool, our goal is to identify pathways and mechanisms that regulate this central apoptosis machinery. In specific, we are studying how the activities of BH3-only proteins, key activators of apoptosis, are controlled during C. elegans development. Our studies have revealed that the control of BH3-only proteins is very complex and most likely conserved. In addition, we have found that the pathways that control the activities of BH3-only proteins have additional important functions during development.

CEM - muscle cell interaction: Signaling for survival. Confocal microscopy.

Regulation and function of mitochondrial dynamics

Mitochondria, the ‘power plants’ of cells, are highly dynamic organelles that constantly fuse and divide.  The balance between mitochondrial fusion and fission determines mitochondrial morphology, which varies from tissue to tissue. What controls mitochondrial fusion and fission is largely unknown. Furthermore the functional significance of mitochondrial dynamics is still an enigma. Interestingly, mitochondrial dynamics has been implicated in processes such as aging and appears to play a role in disorders such as neurodegenerative diseases.Using C. elegans as a tool, we have begun to investigate the regulation and function of mitochondrial dynamics. We have recently discovered that BCL2-like proteins, which are known for their roles in apoptosis, have important functions in the regulation of mitochondrial dynamics as well. Specifically, they modulate the activities of dynamin-related GTPases,which are required for mitochondrial fusion and fission. Currently we are searching for factors that determine cell-type specific mitochondrial morphology. In addition, we are analyzing mitochondrial morphology at different developmental stages and in various mutant backgrounds.

mitochondria-conradt mitochondrial-networks_conradt mitochondrial-tissue-conradt
Dividing mitochondria:
Cellular mechanisms.
Electron microscopy.
Mitochondrial networks:
Connectivity and dynamics
Real-time photoactivation experiment
Tissue-specific mitochondrial morphology:
Fluorescence microscopy