Publication Date:
2015-01-09
Description:
Functional regeneration after nervous system injury requires transected axons to reconnect with their original target tissue. Axonal fusion, a spontaneous regenerative mechanism identified in several species, provides an efficient means of achieving target reconnection as a regrowing axon is able to contact and fuse with its own separated axon fragment, thereby re-establishing the original axonal tract. Here we report a molecular characterization of this process in Caenorhabditis elegans, revealing dynamic changes in the subcellular localization of the EFF-1 fusogen after axotomy, and establishing phosphatidylserine (PS) and the PS receptor (PSR-1) as critical components for axonal fusion. PSR-1 functions cell-autonomously in the regrowing neuron and, instead of acting in its canonical signalling pathway, acts in a parallel phagocytic pathway that includes the transthyretin protein TTR-52, as well as CED-7, NRF-5 and CED-6 (refs 9, 10, 11, 12). We show that TTR-52 binds to PS exposed on the injured axon, and can restore fusion several hours after injury. We propose that PS functions as a 'save-me' signal for the distal fragment, allowing conserved apoptotic cell clearance molecules to function in re-establishing axonal integrity during regeneration of the nervous system.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Neumann, Brent -- Coakley, Sean -- Giordano-Santini, Rosina -- Linton, Casey -- Lee, Eui Seung -- Nakagawa, Akihisa -- Xue, Ding -- Hilliard, Massimo A -- GM059083/GM/NIGMS NIH HHS/ -- GM079097/GM/NIGMS NIH HHS/ -- GM088241/GM/NIGMS NIH HHS/ -- P40 OD010440/OD/NIH HHS/ -- R01 NS060129/NS/NINDS NIH HHS/ -- England -- Nature. 2015 Jan 8;517(7533):219-22. doi: 10.1038/nature14102.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉CJCADR, Queensland Brain Institute, The University of Queensland, Brisbane QLD 4072, Australia. ; Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25567286" target="_blank"〉PubMed〈/a〉
Keywords:
ATP-Binding Cassette Transporters/metabolism
;
Animals
;
Apoptosis/*physiology
;
Axons/*metabolism/pathology
;
Caenorhabditis elegans/*cytology/*metabolism
;
Caenorhabditis elegans Proteins/genetics/*metabolism
;
Carrier Proteins/metabolism
;
Growth Cones/metabolism
;
Membrane Glycoproteins/*metabolism
;
Mutation
;
Nerve Regeneration/*physiology
;
Phagocytes/metabolism
;
Phagocytosis
;
Phosphatidylserines/metabolism
;
Phosphoproteins/metabolism
;
Receptors, Cell Surface/metabolism
;
Signal Transduction
;
Spectrin/genetics/metabolism
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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