Related Experiment Video
Updated: Jul 13, 2026

In vivo Imaging of Optic Nerve Fiber Integrity by Contrast-Enhanced MRI in Mice
Published on: July 22, 2014
Metallothionein-IIA promotes neurite growth via the megalin receptor
Melinda Fitzgerald1, Pia Nairn, Carole A Bartlett
1Experimental and Regenerative Neurosciences, School of Animal Biology, University of Western Australia, Hackett Drive, Crawley 6009, WA, Australia. melfitz1@cyllene.uwa.edu.au
Abstract:
Metallothionein (MT)-I/II has been shown to be neuroprotective and neuroregenerative in a model of rat cortical brain injury. Here we examine expression patterns of MT-I/II and its putative receptor megalin in rat retina. At neonatal stages, MT-I/II was present in retinal ganglion cells (RGCs) but not glial or amacrine cells; megalin was present throughout the retina. Whilst MT-I/II was absent from adult RGC in normal animals and after optic nerve transection, the constitutive megalin expression in RGCs was lost following optic nerve transection. In vitro MT-IIA treatment stimulated neuritic growth: more RGCs grew neurites longer than 25 microm (P < 0.05) in dissociated retinal cultures and neurite extension increased in retinal explants (P < 0.05). MT-IIA treatment of mixed retinal cultures increased megalin expression in RGCs, and pre-treating cells with anti-megalin antibodies prevented MT-IIA-stimulated neurite extension. Our results indicate that MT-IIA stimulates neurite outgrowth in RGCs and may do so via the megalin receptor; we propose that neurite extension is triggered via signal transduction pathways activated by the NPxY motifs of megalin's cytoplasmic tail.
Related Concept Videos
Enzyme-linked Receptors
Neurotrophin (NT) receptors are a family of RTKs, including trkA, trkB, and trkC (tropomyosin-related kinase) receptors. TrkA is specific for nerve growth factor (NGF), neurotrophin-6, and neurotrophin-7. TrkB binds...
Translocation of Proteins into the Mitochondria
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Receptor Downregulation in MVBs
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR activation may...
Ligand-Gated Ion Channel Receptor: Gating Mechanism