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Movement of endoplasmic reticulum in the living axon is distinct from other membranous vesicles in its rate, form, and sensitivity to microtubule inhibitors
Author(s) -
Aihara Yuko,
Inoue Takafumi,
Tashiro Tomoko,
Okamoto Koichi,
Komiya Yoshiaki,
Mikoshiba Katsuhiko
Publication year - 2001
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.1147
Subject(s) - endoplasmic reticulum , nocodazole , microtubule , microbiology and biotechnology , axon , vesicle , biology , axoplasmic transport , synaptophysin , biophysics , chemistry , biochemistry , cytoskeleton , membrane , immunohistochemistry , immunology , cell
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 low 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. J. Neurosci. Res. 65:236–246, 2001. © 2001 Wiley‐Liss, Inc.