Neuronal P2X2 receptors are mobile ATP sensors that explore the plasma membrane when activated.

ATP-gated ionotropic P2X2 receptors are widely expressed in neurons. Although the electrophysiological properties of P2X2 receptors have been extensively studied, little is known about the plasma membrane lateral mobility of P2X2 receptors or whether receptor mobility is regulated by ATP. Here we used single-molecule imaging with simultaneous whole-cell voltage-clamp recordings to track quantum dot-labeled P2X2 receptors in the dendrites of rat hippocampal neurons to explore P2X2 receptor mobility and its regulation.

Regulation of P2X2 receptors by the neuronal calcium sensor VILIP1.

Extracellular adenosine triphosphate (ATP) activates P2X receptors, which are involved in diverse physiological functions. Using a proteomic approach, we identified the neuronal calcium sensor VILIP1 as interacting with P2X2 receptors. We found that VILIP1 forms a signaling complex in vitro and in vivo with P2X2 receptors and regulates P2X2 receptor sensitivity to ATP, peak response, surface expression, and diffusion.

Tracking transmitter-gated P2X cation channel activation in vitro and in vivo.

We present a noninvasive approach to track activation of ATP-gated P2X receptors and potentially other transmitter-gated cation channels that show calcium fluxes. We genetically engineered rat P2X receptors to carry calcium sensors near the channel pore and tested this as a reporter for P2X(2) receptor opening. The method has several advantages over previous attempts to image P2X channel activation by fluorescence resonance energy transfer (FRET): notably, it reports channel opening rather than a conformation change in the receptor protein.

A quantitative regional expression profile of EAAT2 known and novel splice variants reopens the question of aberrant EAAT2 splicing in disease.

The glutamate transporter 1 (GLT1) in rodents, or EAAT2 in humans, is alternatively spliced in a complex manner including the use of multiple 5' and 3' untranslated regions and several coding variants. We used quantitative RT-PCR to profile these splice variants in human and rat brain. We also used RT-PCR and Northern blotting to demonstrate that a novel isoform of GLT1b has an approximately 11kb 3' UTR extending through intron 9, exon 10 and approximately 5kb into the 3' untranslated region of GLT1.

Autism and ultraconserved non-coding sequence on chromosome 7q.

Objective: Autism has been linked to a broad region on chromosome 7q that contains a large number of genes involved in transcription and development. This region is also enriched for ultraconserved non-coding elements, defined as human-rodent sequences that are 100% aligned over > or =200 base pairs, which have a high likelihood of being functional. Therefore, as only a few rare coding variants have been detected in the autism candidate genes on 7q examined to date, we decided to screen these ultraconserved elements for possible autism susceptibility alleles.