How to build a glycinergic postsynaptic membrane

The inhibitory glycine receptor (GlyR) is a ligandgated chloride channel protein found at many synapses of the mammalian central nervous system. During development, distinct isoforms of the GlyR are generated by the sequential expression of different α subunit variants. The appearance of adult type GlyRs in spinal cord is accompanied by the accumulation of a 93 x 10³M(r) receptor-associated peripheral membrane protein. The latter has been localized at the cytoplasmic face of glycinergic postsynaptic membranes and is thought to anchor GlyRs beneath glycinergic nerve terminals. The 93 x 10³M(r) protein binds with high affinity to polymerized tubulin, suggesting that it functions as a receptor-micro tubule linking component. Our data suggest that the interaction of developmentally regulated receptor isoforms with specialized microtubule-associated proteins represents a crucial step in the assembly of postsynaptic receptor matrices.