N-glycosylation in isolated rat nerve terminals

N-linked glycosylation is a ubiquitous protein modification that is capable of modulating protein structure, function and interactions. Many proteins in the brain associated with the synapse and important for synaptic...

Depolarization-dependent Induction of Site-specific Changes in Sialylation on N-linked Glycoproteins in Rat Nerve Terminals

Synaptic transmission leading to release of neurotransmitters in the nervous system is a fast and highly dynamic process. Previously, protein interaction and phosphorylation have been thought to be the main regulators of synaptic transmission. Here we show that sialylation of N-linked glycosylation is a novel potential modulator of neurotransmitter release mechanisms by investigating depolarization-dependent changes of formerly sialylated N-linked glycopeptides. We suggest that negatively charged sialic acids can be modulated, similarly to phosphorylation, by the action of sialyltransferases and sialidases thereby changing local structure and function of membrane glycoproteins. We characterized site-specific alteration in sialylation on N-linked glycoproteins in isolated rat nerve terminals after brief depolarization using quantitative sialiomics. We identified 1965 formerly sialylated N-linked glycosites in synaptic proteins and found that the abundances of 430 glycosites changed after 5 s depolarization. We observed changes on essential synaptic proteins such as synaptic vesicle proteins, ion channels and transporters, neurotransmitter receptors and cell adhesion molecules. This study is to our knowledge the first to describe ultra-fast site-specific modulation of the sialiome after brief stimulation of a biological system.

Synaptic transmission induces site-specific changes in sialylation on N-linked glycoproteins in rat nerve terminals

Synaptic transmission leading to release of neurotransmitters in the nervous system is a fast and highly dynamic process. Previously, protein interaction and phosphorylation have been thought to be the main regulators of synaptic transmission. Here we show a novel potential modulator of synaptic transmission, sialylation of N-linked glycosylation. The negatively charged sialic acids can be modulated, similarly to phosphorylation, by the action of sialyltransferases and sialidases thereby changing local structure and function of membrane glycoproteins. We characterized site-specific alteration in sialylation on N-linked glycoproteins in isolated rat nerve terminals after brief depolarization using quantitative sialiomics. We identified 1965 formerly sialylated N-linked glycosites in synaptic proteins and found that the abundances of 430 glycosites changed after five seconds depolarization. We observed changes on essential synaptic proteins such as synaptic vesicle proteins, ion channels and transporters, neurotransmitter receptors and cell adhesion molecules. This study is to our knowledge the first to describe ultra-fast site-specific modulation of the sialiome after brief stimulation of a biological system.

Sciatic Nerve Regeneration Using Collagen Tubes and Acellular Nerve Transplants in Rabbits (A comparative study)

The present study was conducted to evaluate and compare on anatomical bases between the different types of nerve graft, autograft, collagen tubes (natural polymers), and acellular epineurial nerve sheaths (biological conduits), which included acellular rabbit nerve graft and acellular rat nerve graft. Fourty local breaded rabbits were used and divided into four groups, each of ten rabbits. Then each group was subdivided again into two subgroups according to time of scarifying, which was after 45 days and 3 months post operation. All animals were undergone surgical operation on the right thigh and sciatic nerve of 8-10mm section was sectioned at the mid thigh, and the gap was replaced with the previous graft types comparison was made between the right (experimental) and left thighs (control) side. Samples from proximal, middle and distal stumps were taken to evaluate the regeneration process. The gross results revealed that, most animals developed ulcer formation and others with bone exposure. All animal groups of both periods showed delay latency. All these manifestations appeared as a subsequent of Wallerian degeneration with effects of nerve graft guidance extra cellular matrix, Schwann-macrophage interactions, neurons death and surgical scarring. http://dx.doi.org/10.25130/tjps.25.2020.003