Projects / Programmes
Molecular Cell Physiology”
January 1, 1999
- December 31, 2003
| Code |
Science |
Field |
Subfield |
| 3.03.00 |
Medical sciences |
Neurobiology |
|
| Code |
Science |
Field |
| B470 |
Biomedical sciences |
Physiology |
| B002 |
Biomedical sciences |
Biophysics |
| T490 |
Technological sciences |
Biotechnology |
| B480 |
Biomedical sciences |
Endocrinology, secreting systems, diabetology |
| B210 |
Biomedical sciences |
Histology, cytochemistry, histochemistry, tissue culture |
| B140 |
Biomedical sciences |
Clinical physics, radiology, tomography, medical instrumentation |
Researchers (8)
Organisations (1)
Abstract
The research programme “Molecular Cell Physiology” focuses on the study of molecular mechanisms of exocytosis and on the pathophysiology of mitochondria.
Release of neurotransmitters and hormones from cells is mediated by fusion of vesicle membrane with the plasmamembrane (exocytosis). Practically all cells in the human body perform exocytosis, however the molecular mechanisms of this universal process are poorly understood. Tenths of proteins seem to play a role in exocytosis, but how and in what sequence these proteins interact to mediate exocytosis is not known. On one side it is proposed that a minimal common molecular scaffold is required to escort a vesicle through sequential steps of exocytosis. On the other side data are indicating paralell pathways of exocytosis. To test these hypotheses we are studying secretory activity of a number of cells (pituitary and glial cells, photoreceptors, chondrocytes, adipocytes). Secretory activity is monitored electrophysiologically by measuring membrane capacitance, a parameter related to plasmamembrane surface area. Regulated exocytosis is triggered by a rise in cytoplasmic calcium, therefore we are using flash photolysis of cage compounds to release calcium ions upon a UV flash illumination, which is monitored by calcium fluorescence indicators. The role of proteins in secretory activity is studied by microinjecting probes to manipulate target proteins (antisense technology, recombinant proteins, antibodies, toxins)
Physiological state of mitochondria is associated with a number of diseases (i.e. Alzheimer’s and Parkinson’s diseases, muscular dystrophies, diabetes type II) and with ageing, most likely because these organelles are an initiator of cell death (apoptosis). To study apoptosis we introduced studies on isolated mitochondria. The functioning of mitochondria is monitored by measurements of transmitochondrial potential. It is currently not known whether membrane potential recovers after the initiation of apoptosis. However it is known that energy in the form of ATP is required for this process. We will study this problem by activating apoptosis in the presence of several inhibitors and uncouplers. Apoptosis is associated with the translocation of several proteins from or into mitochondria (i.e. Bcl-2, Bax), however the relationship between these mechanisms and the functioning of mitochondria is not know. We will express these proteins as fusion proteins and will monitor their translocation in cells by using confocal microscopy, while the functional status of mitochondria will be monitored by membrane potential measurements. Classical biochemical approaches will be used to determine the localization of these proteins in mitochondria.
Most important scientific results
Final report
Most important socioeconomically and culturally relevant results
Final report
