VAMP3 VAMP7 control and replenishment of the PLP protein important for development of myelin sheaths

Scientists at the Johannes Gutenberg University of Mainz (JGU) have discovered an important mechanism that influences the formation of the myelin sheath of axons of nerve cells. This mechanism is turned off on purpose, does the transport of myelin components is no longer normal. The Mainz biologists conduct research for 5 years in this field and hope that a better understanding of myelin formation is the future help to develop new regenerative therapies for demyelinating diseases. A loss of the myelin sheath is, for example, the cause of multiple sclerosis (MS).

Photo: © J. Amphornrat Functional analysis of myelin formation in vitro: oligodendrocytes (green) wrap around conductive Nervenzellaxone signal (red) with their cell processes and thereby form the insulating myelin sheath.

Axons are able to stimuli with a velocity of about 100m / s to run through our body. The long extensions of nerve cells to make use of the so-called saltatory conduction, the electrical impulses do not run evenly through the nerve cells, but to jump from node to node. Constriction rings between the axons are surrounded by an insulating sheath, the myelin.

Specialized brain cells that oligodendrocytes wrap, served with a portion of the axon with its own projections at the same time and that up to 50 membrane layers and this is not only a place but as required in many sections of the axon. "This is a tremendous achievement for which needs an oligodendrocyte a sophisticated and finely tuned transport system to the necessary building materials purposefully and in good time to get on the spot," said Dr. Eva-Maria Kramer-Albers of the Department of Molecular Cell Biology and biology for the medical JGU. As the vonstattengeht exactly, is hardly known.

In the group of Kramer-Albers, it was possible to demonstrate a mechanism that regulates the logistics part. Accordingly, the transport of the protein important for the construction of the layers of myelin, the proteolipid protein (PLP), two other proteins, controls the target control the load in the interior of oligodendrocytes: VAMP3 and VAMP7. If these two proteins are switched off in a cell culture, the transport of PLP is reduced significantly - the most when both were simultaneously removed. In genetically modified mice, the myelin formation was however normal even in the absence VAMP3, but was changed to inactive VAMP7. "We think that VAMP7 is an important cog in the machinery of membrane transport by the PLP-supply for incorporation into the myelin membrane regulates," said Jesa Amphornrat, who participated as part of her doctoral work in the investigations. In the future, the Mainz cell biologists in both animal studies off vamps and see if there is a direct link to diseases.

Source: Johannes Gutenberg University of Mainz