Phosphorylation of adhesion- and growth-regulatory human galectin-3 leads to the induction of axonal branching by local membrane L1 and ERM redistribution.
Serine phosphorylation of the beta-galactoside-binding protein galectin-3 (Gal-3) impacts nuclear localization but has unknown consequences for extracellular activities. Herein, we reveal that the phosphorylated form of galectin-3 (pGal-3), adsorbed to substratum surfaces or to heparan sulphate proteoglycans, is instrumental in promoting axon branching in cultured hippocampal neurons by local actin destabilization. pGal-3 interacts with neural cell adhesion molecule L1, and enhances L1 association with Thy-1-rich membrane microdomains. Concomitantly, membrane-actin linker proteins ezrin-radixin-moesin (ERM) are recruited to the same membrane site via interaction with the intracellular domain of L1. We propose that the local regulation of the L1-ERM-actin pathway, at the level of the plasma membrane, underlies pGal-3-induced axon branching, and that galectin phosphorylation in situ could act as a molecular switch for the axon response to Gal-3.
Díez-Revuelta
Natalia
N
Membrane Biology and Axonal Repair Laboratory. Hospital Nacional de Parapléjicos (SESCAM), Finca La Peraleda s/n, E-45071 Toledo, Spain.
Velasco
Silvia
S
André
Sabine
S
Kaltner
Herbert
H
Kübler
Dieter
D
Gabius
Hans-Joachim
HJ
Abad-Rodríguez
José
J
D000199:Actins / Q000378:metabolism; D000818:Animals; D001369:Axons / Q000187:drug effects*; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D037502:Galectin 3 / Q000378:metabolism* / Q000494:pharmacology*; D006624:Hippocampus / Q000166:cytology; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D039842:Neural Cell Adhesion Molecule L1 / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding / Q000187:drug effects / Q000235:genetics; D021381:Protein Transport / Q000187:drug effects / Q000235:genetics; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D017923:Sodium-Hydrogen Exchangers
D000199:Actins; D002352:Carrier Proteins; D037502:Galectin 3; D039842:Neural Cell Adhesion Molecule L1; D010750:Phosphoproteins; D017923:Sodium-Hydrogen Exchangers; C093376:sodium-hydrogen exchanger regulatory factor