The vertebrate muscle Z-disc: sarcomere anchor for structure and signalling

The Z-disc, appearing as a fine dense line forming sarcomere boundaries in striated muscles, when studied in detail reveals crosslinked filament arrays that transmit tension and house myriads of proteins with diverse functions. At the Z-disc the barbed ends of the antiparallel actin filaments from adjoining sarcomeres interdigitate and are crosslinked primarily by layers of α-actinin. The Z-disc is therefore the site of polarity reversal of the actin filaments, as needed to interact with the bipolar myosin filaments in successive sarcomeres. The layers of α-actinin determine the Z-disc width: fast fibres have narrow (~30–50 nm) Z-discs and slow and cardiac fibres have wide (~100 nm) Z-discs. Comprehensive reviews on the roles of the numerous proteins located at the Z-disc in signalling and disease have been published; the aim here is different, namely to review the advances in structural aspects of the Z-disc

Thought bite: A case study of the social construction of a crime and justice concept

The social construction of copycat crime exhibits a process in which a new criminological meme developed first as a media construct and subsequently as a criminological concept. How common the sequence where criminologists follow the media in the construction of crime and justice reality is unknown. The examination of the social construction of copycat crime suggested that the media create a new crime and justice construct through increased usage and modification of either newly minted or previously existing phrases that are disseminated as new crime and justice memes. In the case of copycat crime, media usage and public acceptance foreshadowed criminologists use of the phrase. A multi-step social construction process is hypothesized. A new construct becomes established and accepted in the public lexicon and popular media content; criminology researchers and practitioners note the increased public interest; renamed and reinvigorated research follows, and successful constructs become validated crime and justice phenomena. Employing the social construction history of copycat crime as a case study, this article details the social construction activities in the public and media spheres that created receptive environments for a unique new criminological construct to be developed. Traced from the inception of its component parts to its birth and adoption, the social construction of copycat crime demonstrates a useful methodology for the study of other crime and justice constructions and suggests that the relationship between criminology and the media regarding the social construction of crime and justice be further explored