Intracellular redirection of plasma membrane trafficking after loss of epithelial cell polarity.

In polarized Madin-Darby canine kidney epithelial cells, components of the plasma membrane fusion machinery, the t-SNAREs syntaxin 2, 3, and 4 and SNAP-23, are differentially localized at the apical and/or basolateral plasma membrane domains. Here we identify syntaxin 11 as a novel apical and basolateral plasma membrane t-SNARE. Surprisingly, all of these t-SNAREs redistribute to intracellular locations when Madin-Darby canine kidney cells lose their cellular polarity. Apical SNAREs relocalize to the previously characterized vacuolar apical compartment, whereas basolateral SNAREs redistribute to a novel organelle that appears to be the basolateral equivalent of the vacuolar apical compartment. Both intracellular plasma membrane compartments have an associated prominent actin cytoskeleton and receive membrane traffic from cognate apical or basolateral pathways, respectively. These findings demonstrate a fundamental shift in plasma membrane traffic toward intracellular compartments while protein sorting is preserved when epithelial cells lose their cell polarity.

Syntaxin 11 is associated with SNAP-23 on late endosomes and the trans-Golgi network.

SNARE proteins are known to play a role in regulating intracellular protein transport between donor and target membranes. This docking and fusion process involves the interaction of specific vesicle-SNAREs (e.g. VAMP) with specific cognate target-SNAREs (e.g. syntaxin and SNAP-23). Using human SNAP-23 as the bait in a yeast two-hybrid screen of a human B-lymphocyte cDNA library, we have identified the 287-amino-acid SNARE protein syntaxin 11. Like other syntaxin family members, syntaxin 11 binds to the SNARE proteins VAMP and SNAP-23 in vitro and also exists in a complex with SNAP-23 in transfected HeLa cells and in native human B lymphocytes. Unlike other syntaxin family members, no obvious transmembrane domain is present in syntaxin 11. Nevertheless, syntaxin 11 is predominantly membrane-associated and colocalizes with the mannose 6-phosphate receptor on late endosomes and the trans-Golgi network. These data suggest that syntaxin 11 is a SNARE that acts to regulate protein transport between late endosomes and the trans-Golgi network in mammalian cells.

[Prevalence of bacterial vaginitis and vaginosis: association with clinical and laboratory features, and treatment]. / Prevalencia de vaginitis y vaginosis bacteriana: asociación con manifestaciones clínicas, de laboratorio y tratamiento.

This was a cross-sectional study meant to determine the prevalence of vaginitis and bacterial vaginosis among open population females from Cuernavaca City. The relationship between clinical manifestations, laboratory diagnosis and response to therapy were evaluated as well. A group of 405 sexually active women were enrolled between January and July, 1994. The patients were attending the City Hospital for a regular gynecological consultation, upon their informed consent, they answered a specifically designed questionnaire and had a vaginal secretion sampling. Cotton swabs containing such secretions were employed to measure pH, estimate amines production (fishy odor) and perform both direct microscopic examination and Gram stained smears, which allowed the recognition of yeasts, Trichomonas vaginalis, "clue" cells and normal microflora. Treatments were clotrimazole for candidiasis and metronidazole for trichomoniasis and bacterial vaginosis. Data obtained were analyzed with statistical programs SPSS/PC and EGRET. Overall, 193 out of 405 women (47.7%) had some genital infection; most frequent was candidiasis with a prevalence of 105/405 (26%), bacterial vaginosis and trichomoniasis were present in 67/405 (16.5%) and 7/405 (1.7%) of the population, respectively. Clinical features associated to candidiasis were vulvar itching, dyspareunia, vulvar and cervical erythema, cervical inflammation and vaginal secretion. The only sign consistently observed in bacterial vaginosis patients was a yellow secretion. Women with T. vaginalis showed cervical lesions, friability, microhemorragic zones and vaginal secretion. One important factor linked to bacterial vaginosis was to have had premature labor. Therapeutic responses, with clinical and microbiological cure, were 92% for candidiasis; 93% for bacterial vaginosis; and 100% for trichomoniasis. In conclusion, it is of relevance to stimulate sexually active women to care for their genital health to medically diagnose, avoid and control the very common infections assessed in this paper.