Ammodytoxin, a neurotoxic secreted phospholipase A(2), can act in the cytosol of the nerve cell.
Recent identification of intracellular proteins that bind ammodytoxin (calmodulin, 14-3-3 proteins, and R25) suggests that this snake venom presynaptically active phospholipase A(2) acts intracellularly. As these ammodytoxin acceptors are cytosolic and mitochondrial proteins, the toxin should be able to enter the cytosol of a target cell and remain stable there to interact with them. Using laser scanning confocal microscopy we show here that Alexa-labelled ammodytoxin entered the cytoplasm of the rat hippocampal neuron and subsequently also its nucleus. The transport of proteins into the nucleus proceeds via the cytosol of a cell, therefore, ammodytoxin passed the cytosol of the neuron on its way to the nucleus. Although it is not yet clear how ammodytoxin is translocated into the cytosol of the neuron, our results demonstrate that its stability in the cytosol is not in question, providing the evidence that the toxin can act in this cellular compartment.
Petrovic
Uros
U
Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Ljubljana, Slovenia.
Sribar
Jernej
J
Paris
Alenka
A
Rupnik
Marjan
M
Krzan
Mojca
M
Vardjan
Nina
N
Gubensek
Franc
F
Zorec
Robert
R
Krizaj
Igor
I
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D012910:Snake Venoms / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors; D014757:Viper Venoms / Q000737:chemistry / Q000378:metabolism*
D012910:Snake Venoms; D014757:Viper Venoms; C068117:ammodytoxin A; D010741:Phospholipases A