Dynamics of glycolipid domains in the plasma membrane of living cultured neurons, following protein kinase C activation: a study performed by excimer-formation imaging.
Dynamic changes of glycolipid domains within the plasma membranes of cultured rat cerebellar granule cells have been investigated. For this purpose, a pyrene-labelled derivative of G(M1) ganglioside has been incorporated in the cell plasma membrane, and the rate of excimer formation, directly related to the formation of domains, has been studied by a fluorescence imaging technique (excimer-formation imaging). Fluorescence imaging showed that upon addition of 100 microM glutamate, indirectly inducing the activation of protein kinase C (PKC), glycolipid concentration within domains increases in cell bodies. Comparable effects were exerted by the addition of PMA, directly inducing the activation of PKC. On the contrary, the phorbol ester was not effective in the presence of the specific PKC inhibitor, bisindolylmaleimide. These results suggest that glycolipid-enriched domains are dynamic supramolecular structures affected by membrane-associated events, such as PKC activation. Dynamic changes of domains could be important in modulating their postulated participation in a series of functions, including signal transduction and lipid/protein sorting.
Pitto
M
M
Dipartimento di Chimica e Biochimica Medica, Via Saldini 50, 20133 Milano, Italy. marina.pitto@unimi.it
Palestini
P
P
Ferraretto
A
A
Flati
S
S
Pavan
A
A
Ravasi
D
D
Masserini
M
M
Bottiroli
G
G
D000818:Animals; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D002531:Cerebellum / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D004705:Endocytosis; D004789:Enzyme Activation / Q000187:drug effects; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes; D006017:Glycolipids / Q000737:chemistry* / Q000378:metabolism; D008560:Membrane Fluidity; D008563:Membrane Lipids / Q000737:chemistry* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D013050:Spectrometry, Fluorescence; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D005456:Fluorescent Dyes; D006017:Glycolipids; D008563:Membrane Lipids; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate