By conveying signals from the small GTPase family of proteins to the Arp2/3 complex, proteins of the WAVE family facilitate actin remodeling. The WAVE-1 isoform is expressed at high levels in brain, where it plays a role in normal synaptic processing, and is implicated in hippocampus-dependent memory retention. We used electron microscopy to determine whether synaptic structure is modified in the hippocampus of WAVE-1 knockout mice, focusing on the neuropil of CA1 stratum radiatum. Mice lacking WAVE-1 exhibited alterations in the morphology of both axon terminals and dendritic spines; the relationship between the synaptic partners was also modified. The abnormal synaptic morphology we observed suggests that signaling through WAVE-1 plays a critical role in establishing normal synaptic architecture in the rodent hippocampus.

Background: Based on its distribution in the brain, ecto-nucleoside triphosphate diphosphohydrolase 3 (NTPDase3) may play a role in the hypothalamic regulation of homeostatic systems, including feeding, sleep-wake behavior and reproduction. To further characterize the morphological attributes of NTPDase3-immunoreactive (IR) hypothalamic structures in the rat brain, here we investigated: 1.) The cellular and subcellular localization of NTPDase3; 2.) The effects of 17β-estradiol on the expression level of hypothalamic NTPDase3; and 3.) The effects of NTPDase inhibition in hypothalamic synaptosomal preparations.

The alpha- and beta-dystrobrevins (DBs) belong to a family of dystrophin-related and dystrophin-associated proteins that are members of the dystrophin-associated protein complex (DAPC). This complex provides a link between the cytoskeleton and the extracellular matrix or other cells. However, specific functions of the two dystrobrevins remain largely unknown, with alpha-DB being believed to have a role mainly in skeletal muscle. Here, we describe previously unknown expression patterns and the localisation and molecular characteristics of alpha-DB isoforms in non-muscle mouse tissues. We demonstrate a highly specific sub-cellular distribution of alpha-DB in organs forming blood-tissue barriers. We show alpha-DB expression and localisation in testicular Sertoli cells, stomach and respiratory epithelia and provide electron-microscopic evidence for its immunolocalisation in these cells and in the central nervous system. Moreover, we present the molecular characterisation of alpha-DB transcript in these tissues and provide evidence for a distinct heterogeneity of associations between alpha-DB and dystrophins and utrophin in normal and dystrophic non-muscle tissues. Together, our results indicate that alpha-DB, in addition to its role in skeletal muscle, may also be required for the proper function of specific non-muscle tissues and that disruption of DAPC might lead to tissue-blood barrier abnormalities.

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