Translocation of dynorphin neuropeptides across the plasma membrane. A putative mechanism of signal transmission.
Several peptides, including penetratin and Tat, are known to translocate across the plasma membrane. Dynorphin opioid peptides are similar to cell-penetrating peptides in a high content of basic and hydrophobic amino acid residues. We demonstrate that dynorphin A and big dynorphin, consisting of dynorphins A and B, can penetrate into neurons and non-neuronal cells using confocal fluorescence microscopy/immunolabeling. The peptide distribution was characterized by cytoplasmic labeling with minimal signal in the cell nucleus and on the plasma membrane. Translocated peptides were associated with the endoplasmic reticulum but not with the Golgi apparatus or clathrin-coated endocytotic vesicles. Rapid entry of dynorphin A into the cytoplasm of live cells was revealed by fluorescence correlation spectroscopy. The translocation potential of dynorphin A was comparable with that of transportan-10, a prototypical cell-penetrating peptide. A central big dynorphin fragment, which retains all basic amino acids, and dynorphin B did not enter the cells. The latter two peptides interacted with negatively charged phospholipid vesicles similarly to big dynorphin and dynorphin A, suggesting that interactions of these peptides with phospholipids in the plasma membrane are not impaired. Translocation was not mediated via opioid receptors. The potential of dynorphins to penetrate into cells correlates with their ability to induce non-opioid effects in animals. Translocation across the plasma membrane may represent a previously unknown mechanism by which dynorphins can signal information to the cell interior.
Marinova
Zoya
Z
Section of Alcohol and Drug Dependence Research, Department of Clinical Neuroscience, Karolinska Institute, S-17176 Stockholm, Sweden.
Vukojevic
Vladana
V
Surcheva
Slavina
S
Yakovleva
Tatiana
T
Cebers
Gvido
G
Pasikova
Natalia
N
Usynin
Ivan
I
Hugonin
Loïc
L
Fang
Weijie
W
Hallberg
Mathias
M
Hirschberg
Daniel
D
Bergman
Tomas
T
Langel
Ulo
U
Hauser
Kurt F
KF
Pramanik
Aladdin
A
Aldrich
Jane V
JV
Gräslund
Astrid
A
Terenius
Lars
L
Bakalkin
Georgy
G
D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D002531:Cerebellum / Q000378:metabolism; D002942:Circular Dichroism; D002966:Clathrin / Q000737:chemistry; D003593:Cytoplasm / Q000378:metabolism; D004399:Dynorphins / Q000737:chemistry*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D018613:Microscopy, Confocal; D009474:Neurons / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*; D016716:PC12 Cells; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D021381:Protein Transport; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D021241:Spectrometry, Mass, Electrospray Ionization; D013997:Time Factors
D002966:Clathrin; D009479:Neuropeptides; D010455:Peptides; D004399:Dynorphins