TY - JOUR
T1 - Evolution of the spatial distribution of MAP1B phosphorylation sites in vertebrate neurons
AU - Tymanskyj, Stephen R.
AU - Lin, Shen
AU - Gordon-Weeks, Phillip R.
PY - 2010/6
Y1 - 2010/6
N2 - The microtubule-associated protein MAP1B has important roles in neural development, particularly in migrating and differentiating neurons. MAP1B is phosphorylated by glycogen synthase kinase 3 beta (GSK-3 beta) at a site that requires prior phosphorylation by another kinase four amino acid residues downstream of the GSK-3 beta site, a so-called primed site, and at non-primed sites that have no such requirement. In developing mammalian neurons, MAP1B phosphorylated by GSK-3 beta at primed and non-primed sites is distributed in spatially distinct patterns. Non-primed GSK-3 beta-phosphorylated MAP1B sites are only expressed in axons and are present in the form of a gradient that is highest distally, towards the growth cone. In contrast, primed GSK-3 beta-phosphorylated MAP1B sites are present throughout the neuron including the somato-dendritic compartment and uniformly throughout the axon. To examine the function of these two sites, we explored the evolutionary conservation of the spatial distribution of GSK-3 beta primed and non-primed sites on MAP1B in vertebrate neurons. We immunostained spinal cord sections from embryonic or newly hatched representatives of all of the main vertebrate groups using phospho-specific antibodies to GSK-3 beta primed and non-primed sites on MAP1B. This revealed a remarkable evolutionary conservation of the distribution of primed and non-primed GSK-3 beta-phosphorylated MAP1B sites in developing vertebrate neurons. By analysing amino acid sequences of MAP1B we found that non-primed GSK-3 beta sites are more highly conserved than primed sites throughout the vertebrates, suggesting that the latter evolved later. Finally, distinct distribution patterns of GSK-3 beta primed and non-primed sites on MAP1B were preserved in cultured rat embryonic cortical neurons, opening up the possibility of studying the two sites in vitro.
AB - The microtubule-associated protein MAP1B has important roles in neural development, particularly in migrating and differentiating neurons. MAP1B is phosphorylated by glycogen synthase kinase 3 beta (GSK-3 beta) at a site that requires prior phosphorylation by another kinase four amino acid residues downstream of the GSK-3 beta site, a so-called primed site, and at non-primed sites that have no such requirement. In developing mammalian neurons, MAP1B phosphorylated by GSK-3 beta at primed and non-primed sites is distributed in spatially distinct patterns. Non-primed GSK-3 beta-phosphorylated MAP1B sites are only expressed in axons and are present in the form of a gradient that is highest distally, towards the growth cone. In contrast, primed GSK-3 beta-phosphorylated MAP1B sites are present throughout the neuron including the somato-dendritic compartment and uniformly throughout the axon. To examine the function of these two sites, we explored the evolutionary conservation of the spatial distribution of GSK-3 beta primed and non-primed sites on MAP1B in vertebrate neurons. We immunostained spinal cord sections from embryonic or newly hatched representatives of all of the main vertebrate groups using phospho-specific antibodies to GSK-3 beta primed and non-primed sites on MAP1B. This revealed a remarkable evolutionary conservation of the distribution of primed and non-primed GSK-3 beta-phosphorylated MAP1B sites in developing vertebrate neurons. By analysing amino acid sequences of MAP1B we found that non-primed GSK-3 beta sites are more highly conserved than primed sites throughout the vertebrates, suggesting that the latter evolved later. Finally, distinct distribution patterns of GSK-3 beta primed and non-primed sites on MAP1B were preserved in cultured rat embryonic cortical neurons, opening up the possibility of studying the two sites in vitro.
U2 - 10.1111/j.1469-7580.2010.01228.x
DO - 10.1111/j.1469-7580.2010.01228.x
M3 - Article
VL - 216
SP - 692
EP - 704
JO - Journal of Anatomy
JF - Journal of Anatomy
IS - 6
ER -