Digital fluorescence imaging of trafficking of endosomes containing low-density lipoprotein in brain astroglial cells.
We have used digital fluorescence microscopy to examine transport of LDL-containing endosomes in rat brain astroglial cells to show that individual middle endosomes undergo rapid transitions between forward/backward movements and immobile states over short distances. The population of rapidly moving endosomes (>0.04 microm/sec) was 35. 9%, and the remaining endosomes were slowly moving or temporarily immobile (<0.04 microm/sec). The averaged motion was, however, a very slow perinuclear motion with a velocity of 3.25 microm/h. This small velocity is mainly due to frequent changing of directions in movements, requiring 6 h for a significant concentration around the circumference of the cell nuclei. The application of both anti-dynein antibodies and vanadate in permeabilized cells resulted in peripherally concentrated distribution of endosomes, probably due to inhibition of perinuclear motion by dynein-like motor proteins. These results imply that both dynein-like and kinesin-like proteins bind to the same endosome resulting in both perinuclear and peripherally directed movements.
Ichikawa
T
T
Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, University of Tokyo at Komaba 3-8-1, Meguro, Tokyo, 153, Japan.
Yamada
M
M
Homma
D
D
Cherry
R J
RJ
Morrison
I E
IE
Kawato
S
S
D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D002478:Cells, Cultured; D004398:Dyneins / Q000037:antagonists & inhibitors / Q000502:physiology; D011992:Endosomes / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D016547:Kinesins / Q000502:physiology; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000187:drug effects / Q000502:physiology; D009068:Movement / Q000187:drug effects / Q000502:physiology; D015739:Nocodazole / Q000494:pharmacology; D051381:Rats; D014638:Vanadates / Q000494:pharmacology
D008077:Lipoproteins, LDL; D014638:Vanadates; D004398:Dyneins; D016547:Kinesins; D015739:Nocodazole