TY - JOUR
T1 - Movement of endoplasmic reticulum in the living axon is distinct from other membranous vesicles in its rate, form, and sensitivity to microtubule inhibitors
AU - Aihara, Yuko
AU - Inoue, Takafumi
AU - Tashiro, Tomoko
AU - Okamoto, Koichi
AU - Komiya, Yoshiaki
AU - Mikoshiba, Katsuhiko
PY - 2001/8/1
Y1 - 2001/8/1
N2 - The endoplasmic reticulum (ER) is the major membranous component present throughout the axon. Although other membranous structures such as synaptic vesicles are known to move via fast axonal transport, the dynamics of ER in the axon still remains unknown. To study the dynamics of ER in the axon, we have directly visualized the movement of two ER-specific membrane proteins, the sarcoplasmic/endoplasmic reticulum calcium-ATPase and the inositol 1,4,5-trisphosphate receptor, both of which were tagged with green fluorescence protein (GFP) and expressed in cultured chick dorsal root ganglion neurons. In contrast to GFP-tagged synaptophysin that moved as vesicles at 1 μm/sec predominantly in the anterograde direction in the typical style of fast axonal transport, the two ER proteins did not move in a discrete vesicular form. Their movement determined by the fluorescence recovery after photobleaching technique was bi-directional, 10-fold slower (∼0.1 μm/sec), and temperature-sensitive. The rate of movement of ER was also sensitive to Iow doses of vinblastine and nocodazole that did not affect the rate of synaptophysin-GFP, further suggesting that it is also distinct from the well-documented movement of membranous vesicles in its relation with microtubules.
AB - The endoplasmic reticulum (ER) is the major membranous component present throughout the axon. Although other membranous structures such as synaptic vesicles are known to move via fast axonal transport, the dynamics of ER in the axon still remains unknown. To study the dynamics of ER in the axon, we have directly visualized the movement of two ER-specific membrane proteins, the sarcoplasmic/endoplasmic reticulum calcium-ATPase and the inositol 1,4,5-trisphosphate receptor, both of which were tagged with green fluorescence protein (GFP) and expressed in cultured chick dorsal root ganglion neurons. In contrast to GFP-tagged synaptophysin that moved as vesicles at 1 μm/sec predominantly in the anterograde direction in the typical style of fast axonal transport, the two ER proteins did not move in a discrete vesicular form. Their movement determined by the fluorescence recovery after photobleaching technique was bi-directional, 10-fold slower (∼0.1 μm/sec), and temperature-sensitive. The rate of movement of ER was also sensitive to Iow doses of vinblastine and nocodazole that did not affect the rate of synaptophysin-GFP, further suggesting that it is also distinct from the well-documented movement of membranous vesicles in its relation with microtubules.
KW - ER
KW - FRAP
KW - Inositol 1,4,5-trisphosphate receptor
KW - Microtubule inhibitors
KW - Sarcoplasmic/endoplasmic reticulum calcium ATPase
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U2 - 10.1002/jnr.1147
DO - 10.1002/jnr.1147
M3 - Article
C2 - 11494358
AN - SCOPUS:0035424533
VL - 65
SP - 236
EP - 246
JO - Journal of Neuroscience Research
JF - Journal of Neuroscience Research
SN - 0360-4012
IS - 3
ER -