Axon sorting

Eggan K, Baldwin K, Tackett M, Osborne J, Gogos J, Chess A, Axel R, Jaenisch R (2004) Mice cloned from olfactory sensory neurons. Nature 428(6978) 44-49 Feinstein P, Mombaerts P (2004) A contextual model for axonal sorting into glomeruli in the mouse olfactory system.Cell 117(6) 817—831... 

Serizawa S, Miyamichi K, Takeuchi H, Yamagishi Y, Suzuki M, Sakano H (2006) A neuronal identity code for the odorant receptor-specific and activity-dependent axon sorting. Cell 127(5) 1057-1069... 

Eeinstein, P., Mombaerts, P. A contextual model for axonal sorting into glomeruli in the mouse olfactory system. Cell 117, 817-831 (2004)... 

The MAPs vary in number and relative abundance in different cell types MAP2 is principally found in dendrites, whereas tau is restricted to axons. This selective distribution of MAP2 molecules is the result of subcellular sorting of its messenger RNA (Lewis et al., 1989). Currently, there is interest in the observation that tau is a component of the neurofibrillary tangles of Alzheimer s disease (Goedert et al., 1989). 

Coy, D.L. Howard, J. (1994). Organelle transport and sorting in axons. Curr. Opin. Neurobiol. 4, 662-667. 

The nerve axon sodium channel was studied in detail (in fact, as shown by the power spectrum analysis, there are two sorts of this channel one with fast opening and slow inactivation and the other with opposite properties). It is a glycoprotein consisting of three subunits (Fig. 6.22), the largest (mol. wt. 3.5 X 105) with a pore inside and two smaller ones (mol.wt 3.5 X 104 and 3.3 X 104). The attenuation in the orifice of the pore is a kind of a filter... 

Vesicular proteins and lipids that are destined for the plasma membrane leave the TGN sorting station continuously. Incorporation into the plasma membrane is typically targeted to a particular membrane domain (dendrite, axon, presynaptic, postsynaptic membrane, etc.) but may or may not be triggered by extracellular stimuli. Exocytosis is the eukaryotic cellular process defined as the fusion of the vesicular membrane with the plasma membrane, leading to continuity between the intravesicular space and the extracellular space. Exocytosis carries out two main functions it provides membrane proteins and lipids from the vesicle membrane to the plasma membrane and releases the soluble contents of the lumen (proteins, peptides, etc.) to the extracellular milieu. Historically, exocytosis has been subdivided into constitutive and regulated (Fig. 9-6), where release of classical neurotransmitters at the synaptic terminal is a special case of regulated secretion [54]. 

Newly synthesized membrane and secretory proteins destined for the axon travel by fast anterograde transport. However, not all membrane-bounded organelles (MBOs) are destined for the axon. As a result, the first stage of transport must be synthesis, sorting and packaging of organelles (see Ch. 9). Once assembled, the organelle must then be committed to the transport... 

Drug studies demonstrated a requirement that most proteins destined for fast axonal transport traverse the Golgi stacks, where membrane proteins are post-transla-tionally modified, sorted and packaged [9] (Fig. 28-7). This suggests that proteins in fast axonal transport must either pass through the Golgi complex or associate with... 

The olfactory epithelium of mammals contains many types of olfactory neurons, each expressing a specific odorant receptor. Linda Buck has shown that an odorant can activate multiple distinct receptors and that a receptor can be activated by multiple odorants. Thus, there must exist a combinatorial mechanism for odor detection some sort of pattern recognition. The axons of olfactory neurons converge on glomeruli in the olfactory bulb. There, incoming signals are integrated and the sense of smell is created. 

The absolute neurospecificity of clostridial neurotoxins, and the ability of TeNT to undergo axonal retrograde transport, make them ideal tools to study endocyto-sis and sorting at the synapse, and of retro-axonal transport both in vitro and in vivo (reviewed in Deinhardt and Schiavo 2005). These processes, which are still poorly understood at the molecular level, represent an exciting area of application for clostridial neurotoxins and their binding fragments. 

Dotti CG, Simons K. Polarized sorting of viral glycoproteins to the axon and dendrites of hippocampal neurons in culture. Cell 1990 62 63-72. 

Sorting the Axon toWrap Signaling in Both Parties... 

Sorting to the final destination TeTx is translocated predominantly by retrograde axonal transport to the axodendritic area of the motoneurons in the spinal cord. Here, the toxin is released, probably by a transcytotic mechanism, crosses the synaptic cleft. 

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