Spectrin-beta 2 facilitates the selective accumulation of GABAA receptors at somatodendritic synapses

Fast synaptic inhibition is dependent on targeting specific GABAAR subtypes to dendritic and axon initial segment (AIS) synapses. Synaptic GABAARs are typically assembled from α1-3, β and γ subunits. Here, we isolate distinct GABAARs from the brain and interrogate their composition using quantitative proteomics. We show that α2-containing receptors co-assemble with α1 subunits, whereas α1 receptors can form GABAARs with α1 as the sole α subunit. We demonstrate that α1 and α2 subunit-containing receptors co-purify with distinct spectrin isoforms; cytoskeletal proteins that link transmembrane proteins to the cytoskeleton. β2-spectrin was preferentially associated with α1-containing GABAARs at dendritic synapses, while β4-spectrin was associated with α2-containing GABAARs at AIS synapses. Ablating β2-spectrin expression reduced dendritic and AIS synapses containing α1 but increased the number of synapses containing α2, which altered phasic inhibition. Thus, we demonstrate a role for spectrins in the synapse-specific targeting of GABAARs, determining the efficacy of fast neuronal inhibition

Reclamation: a Century-old Urban Development Strategy under Fire in Hong Kong

Hong Kong has a long history of creating urban land by reclamation. The leasehold system, coupled with the production of new land, is a major source of government revenue. The executive-led government's objective of economic growth, rather than improving the overall quality of life, to a large degree explains the reclamation strategy. This objective and the means of achieving it, are now being challenged by a democratizing Hong Kong society. The current controversy about the central harbour reclamation is a reflection of this. The paper argues that further large scale harbour reclamation is not sustainable, and recommends that the government work together with its citizens on an integrated urban development strategy comprising urban renewal and better planning of the New Territories in the regional context