The 93-kDa glycine receptor-associated protein binds to tubulin.
A peripheral membrane protein with a relative molecular mass of 93,000 Da is associated with cytoplasmic domains of the inhibitory glycine receptor of mammalian spinal cord. Here, evidence is given that this 93-kDa protein binds to polymerized tubulin. First, tubulin cofractionated with the 93-kDa protein upon affinity purification of the glycine receptor. Second, tubulin bound to the isolated 93-kDa protein in an overlay procedure. Third, in assays containing the purified glycine receptor, the 93-kDa protein as well as the glycine receptor alpha and beta subunits coassembled with tubulin and microtubules. The interaction of the 93-kDa protein with tubulin displayed high affinity (KD approximately 2.5 nM) and significant cooperativity (Hill coefficient approximately 2.1) and approached a stoichiometry of approximately 1:4 under saturating conditions. These data suggest that the 93-kDa protein anchors the glycine receptor at postsynaptic sites via binding to subsynaptic tubulin.
Kirsch
J
J
Abteilung Neurochemie, Max-Planck-Institut für Hirnforschung, Frankfurt, Germany.
Langosch
D
D
Prior
P
P
Littauer
U Z
UZ
Schmitt
B
B
Betz
H
H
D000818:Animals; D001921:Brain / Q000378:metabolism; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D005998:Glycine / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D008870:Microtubules / Q000378:metabolism; D008970:Molecular Weight; D011485:Protein Binding; D051381:Rats; D018009:Receptors, Glycine; D017981:Receptors, Neurotransmitter / Q000302:isolation & purification / Q000378:metabolism*; D013116:Spinal Cord / Q000378:metabolism; D014404:Tubulin / Q000302:isolation & purification / Q000378:metabolism*
D046911:Macromolecular Substances; D018009:Receptors, Glycine; D017981:Receptors, Neurotransmitter; D014404:Tubulin; D005998:Glycine