Faculty Opinions recommendation of Directional cell migration establishes the axes of planar polarity in the posterior lateral-line organ of the zebrafish.

Abstract The arrangement of the lateral line afferents of salamanders as revealed by transganglionic staining with horse radish peroxidase is described. Each lateral line organ is supplied by two fibers only. In the medulla these two afferent fibers run in separate fiber bundles. It is suggested, that only those fibers contacting lateral line sensory cells with the same polarity form together one bundle. Bundles formed by anterior or posterior lateral line afferents are also clearly separated. Beside the lateral line organs smaller pit organs are described. These organs are supplied by one afferent only which reveals an arrangement in the medulla different from that of the lateral line afferents. Based on anatomical facts, these small pit organs are considered to be electroreceptors. Centrifugally projecting neurons, most probably efferents, are described in the medulla.

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Mib1 contributes to persistent directional cell migration by regulating the Ctnnd1-Rac1 pathway

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1712560114 ◽

2017 ◽

Vol 114 (44) ◽

pp. E9280-E9289 ◽

Cited By ~ 12

Author(s):

Takamasa Mizoguchi ◽

Shoko Ikeda ◽

Saori Watanabe ◽

Michiko Sugawara ◽

Motoyuki Itoh

Keyword(s):

Cell Migration ◽

Lateral Line ◽

Wound Closure ◽

Cultured Cells ◽

Small Gtpase ◽

Precise Control ◽

Animal Development ◽

Posterior Lateral Line ◽

Rac1 Activity ◽

Directional Cell Migration

Persistent directional cell migration is involved in animal development and diseases. The small GTPase Rac1 is involved in F-actin and focal adhesion dynamics. Local Rac1 activity is required for persistent directional migration, whereas global, hyperactivated Rac1 enhances random cell migration. Therefore, precise control of Rac1 activity is important for proper directional cell migration. However, the molecular mechanism underlying the regulation of Rac1 activity in persistent directional cell migration is not fully understood. Here, we show that the ubiquitin ligase mind bomb 1 (Mib1) is involved in persistent directional cell migration. We found that knockdown of MIB1 led to an increase in random cell migration in HeLa cells in a wound-closure assay. Furthermore, we explored novel Mib1 substrates for cell migration and found that Mib1 ubiquitinates Ctnnd1. Mib1-mediated ubiquitination of Ctnnd1 K547 attenuated Rac1 activation in cultured cells. In addition, we found that posterior lateral line primordium cells in the zebrafish mib1ta52b mutant showed increased random migration and loss of directional F-actin–based protrusion formation. Knockdown of Ctnnd1 partially rescued posterior lateral line primordium cell migration defects in the mib1ta52b mutant. Taken together, our data suggest that Mib1 plays an important role in cell migration and that persistent directional cell migration is regulated, at least in part, by the Mib1–Ctnnd1–Rac1 pathway.

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Extracellular Receptor Potentials from the Lateral-Line Organ of Xenopus Laevis

Journal of Experimental Biology ◽

10.1242/jeb.86.1.63 ◽

1980 ◽

Vol 86 (1) ◽

pp. 63-77

Author(s):

ALFONS B. A. KROESE ◽

JOHAN M. VAN DER ZALM ◽

JOEP VAN DEN BERCKEN

Keyword(s):

Xenopus Laevis ◽

Lateral Line ◽

Hair Cells ◽

Water Displacement ◽

Stimulus Amplitude ◽

Nerve Fibres ◽

Large Stimulus ◽

Sensory Hair ◽

Lateral Line Organ ◽

Line Organ

1. The response of the epidermal lateral-line organ of Xenopus laevis to stimulation was studied by recording extracellular receptor potentials from the hair cells in single neuromasts in isolated preparations. One neuromast was stimulated by local, sinusoidal water movements induced by a glass sphere positioned at a short distance from the neuromast. 2. The amplitudes of the extracellular receptor potentials were proportional to the stimulus amplitude over a range of 20 dB. The phase of the extracellular receptor potentials with respect to water displacement was independent of the stimulus amplitude. 3. With large stimulus amplitude, and stimulus frequencies between 0.5 Hz and 2 Hz, the extracellular receptor potentials, and responses of single afferent nerve fibres, showed a phase lead of 1.2 π radians with respect to water displacement, i.e. they were almost in phase with water acceleration. 4. It is concluded that under conditions of stimulation with small-amplitude water movements, the hair cells respond to sensory hair displacement, whereas under conditions of stimulation with large-amplitude water movements they respond to sensory hair velocity.

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