Communication and signal transfer between nerve cells in the brain involve numerous cellular processes. In particular, vesicles, the most abundant organelles in nerve endings, play a major role in this fundamental process. These small cell compartments, which are each surrounded by their own individual membranes, store various chemical substances (neurotransmitters) essential for signal transmission. When an action potential reaches the synapse (the contact point between two nerve cells), calcium channels open, and the vesicle attached to the cell membrane releases its neurotransmitters into the synaptic cleft.
Adjunct Professor Walter Volknandt analyses these chemical processes in nerve cells (neurons) and the surrounding glial cells. He isolates nerve endings (synaptosomes) from rodent brains and investigates the structure and function of vesicles contained in different synaptosomes. Using a proteome analysis, Volknandt previously discovered novel proteins both in and on the vesicular membrane and proved that glucose can be broken down there to create the energy-rich nucleotide adenosine triphosphate (ATP). This process was originally thought to take place exclusively in distant cell bodies of the neurons. Newly generated ATP can, on the one hand, provide energy, which is needed for the fast uptake of neurotransmitters into the vesicles, and on the other hand, serve as an intercellular signalling molecule after its release from the nerve ending.
Volknandt and his group also analyse various other roles of proteins, such as in the generation of new neurons in adult mammal brain (neurogenesis). Moreover, amyloid precursor protein (APP) is already present in embryos and persists throughout adulthood in certain nerve cells. The breakdown of this protein by enzymes is involved in the onset of Alzheimer's disease. Now, Volknandt is eager to discover the physiological functions and interactions of this protein. Discussing his field of research Volknandt says, "The number and interactions of proteins are still largely unknown, and we suspect that the function of many molecules is determined by their position in the cell". Volknandt is involved in the practical and theoretical teaching of students as well as initiating and organising the Master's Programmes in "Interdisciplinary Neuroscience" and "Cell Biology and Physiology", in which he aspires to awaken critical and enquiring minds.
Walter Volknandt studied Biology and Chemistry in Göttingen and submitted his doctoral thesis at the Zoological Institute there on "Protein Synthesis in Single-Cell Organisms". Since 1983 he has headed a neurochemistry research group in the Faculty of Biological Sciences at the Goethe University Frankfurt. His appointment as a private lecturer was followed in 1989 by his Habilitation in "Molecular Components of Cholinergic Synaptic Vesicles". In 1990/91 he spent nine months conducting research at Stanford University, California, U.S.A. Five years later, in 1996, he was appointed an Adjunct Professor in Frankfurt. As part of the academic administration of the University, he is in charge of the governance of various facilities in the Biocentre, such as the animal cell culture and gene technology facilities; in addition, he is radiation protection officer.
Apl. Prof. Dr. Walter Volknandt
Institute of Cell Biology and Neuroscience
Max-von-Laue-Str. 13 (Biologicum, Flügel A)
60438 Frankfurt am Main
Telephone: +49 (0)69 798 42565