Isomin: a novel cytoplasmic intermediate filament protein from an arthropod species

<p>Abstract</p> <p>Background</p> <p>The expression of intermediate filaments (IFs) is a hallmark feature of metazoan cells. IFs play a central role in cell organization and function, acting mainly as structural stress-absorbing elements. There is growing evidence to suggest that these cytoskeletal elements are also involved in the integration of signalling networks. According to their fundamental functions, IFs show a widespread phylogenetic expression, from simple diblastic animals up to mammals, and their constituent proteins share the same molecular organization in all species so far analysed. Arthropods represent a major exception in this scenario. Only lamins, the nuclear IF proteins, have so far been identified in the model organisms analysed; on this basis, it has been considered that arthropods do not express cytoplasmic IFs.</p> <p>Results</p> <p>Here, we report the first evidence for the expression of a cytoplasmic IF protein in an arthropod - the basal hexapod <it>Isotomurus maculatus</it>. This new protein, we named it isomin, is a component of the intestinal terminal web and shares with IFs typical biochemical properties, molecular features and reassembly capability. Sequence analysis indicates that isomin is mostly related to the Intermediate Filament protein C (IFC) subfamily of <it>Caenorhabditis elegans </it>IF proteins, which are molecular constituents of the nematode intestinal terminal web. This finding is coherent with, and provides further support to, the most recent phylogenetic views of arthropod ancestry. Interestingly, the coil 1a domain of isomin appears to have been influenced by a substantial molecular drift and only the aminoterminal part of this domain, containing the so-called helix initiation motif, has been conserved.</p> <p>Conclusions</p> <p>Our results set a new basis for the analysis of IF protein evolution during arthropod phylogeny. In the light of this new information, the statement that the arthropod phylum lacks cytoplasmic IFs is no longer tenable.</p> <p>See commentary article: <url>http://www.biomedcentral.com/1741-7007-9-16</url>.</p

Parapelvic cysts, a distinguishing feature of renal Fabry disease

Background Fabry's disease (FD) is a rare, multi-organ lysosomal disease, caused by the deficiency of the enzyme \u3b1-galactosidase A, and is difficult to diagnose. Although parapelvic cysts (PC) were previously associated with FD, their prevalence and significance are unclear. Methods The present study aimed to: (i) evaluate, by renal ultrasound, the real prevalence of PC and of their determinants in a multicentre, nationwide cohort of FD patients (n = 173, Study 1) and (ii) ascertain whether a greater accuracy of PC detection improved their identification, in FD patients from a single centre (n = 67, Study 2). In both studies, for each FD patient, an age-and renal function-matched subject was selected for comparison (1:1). Results In Study 1, PC were detected in 28.9% of FD subjects and in only 1.1% of control subjects (P < 0.001). The presence of other renal abnormalities did not differ between the groups, nor differences exist in the main demographic and laboratory parameters between the groups. In Study 2, the greater accuracy of ultrasound increased PC prevalence from 29.8% to 43.3% in the same subjects (P < 0.05). In both studies, no correlation was detected between PC and the main demographic, clinical and biochemical parameters, including use of enzyme replacement therapy (P < 0.1, minimum value). Finally, no difference existed between FD patients with and without PC. Conclusions The present study suggests that the presence of PC in renal patients should alert physicians to consider the diagnosis of FD, primarily in subjects with an unclear family history of renal disease and in the presence of other stigmata of the disease