Search results for "Secretor"
showing 10 items of 159 documents
Membrane protein integration into the endoplasmic reticulum
2011
Most integral membrane proteins are targeted, inserted and assembled in the endoplasmic reticulum membrane. The sequential and potentially overlapping events necessary for membrane protein integration take place at sites termed translocons, which comprise a specific set of membrane proteins acting in concert with ribosomes and, probably, molecular chaperones to ensure the success of the whole process. In this minireview, we summarize our current understanding of helical membrane protein integration at the endoplasmic reticulum, and highlight specific characteristics that affect the biogenesis of multispanning membrane proteins.
Norovirus-Host Interactions in the course of Inflammatory Bowel Disease
2021
Inflammatory bowel disease (IBD) affects around 200,000 people in France. This group of conditions includes Crohn's disease (CD), which involves the entire digestive tract, and ulcerative colitis (UC), which involves only the colon and rectum. It is known that immunological, genetic and microbiological factors are at play in IBD, but the role of viruses remains only partially explored. Among viral etiologies, human noroviruses (huNoV) are the main cause of acute viral gastroenteritis worldwide. Norovirus binds to intestinal cells through histo-blood group antigens (HBGA), including ABO and Lewis antigens. The expression of HBGA is dependent upon tissue type and the underlying physiopatholog…
Distribution and coexistence of chromogranin A-, serotonin-and pancreastatin-like immunoreactivity in endocrine-like cells of the human anal canal
1992
The comparative distribution and coexistence of chromogranin A (CGA)-, serotonin (5-hydroxytryptamine; 5-HT)- and pancreastatin (PST)-like immunoreactivity in endocrine-like cells of the human anal canal was investigated by light-microscopic immunocytochemistry. The largest population of colorectal endocrine-like cells consisted of CGA-immunoreactive (ir) cells, followed by the 5-HT-ir and PST-ir cell population. In the anal transitional zone (ATZ), CGA- and 5-HT-immunoreactivity was equally distributed; ir-PST was confined to a smaller endocrine-like cell population. In the squamous zone and the perianal skin, Merkel cells in the basal layer of the epidermis and hair follicles exhibited ir…
Shedding of Membrane Vesicles Mediates Fibroblast Growth Factor-2 Release from Cells
2003
Fibroblast growth factor-2 (FGF-2), a polypeptide with regulatory activity on cell growth and differentiation, lacks a conventional secretory signal sequence, and its mechanism of release from cells remains unclear. We characterized the role of extracellular vesicle shedding in FGF-2 release. Viable cells released membrane vesicles in the presence of serum. However, in serum-free medium vesicle shedding was dramatically down-regulated, and the cells did not release FGF-2 activity into their conditioned medium. Addition of serum to serum-starved cells rapidly induced intracellular FGF-2 clustering under the plasma membrane and into granules that colocalized with patches of the cell membrane …
Apical transport of osteopontin is independent of N-glycosylation and sialylation.
2002
Studies of how epithelial surface polarity into apical and basolateral domains is generated and maintained have proposed that carbohydrate modifications serve as apical targeting signals for proteins by interacting with lectin sorters. However, the experimental evidence in support of N-glycans, O-glycans and sialic acids mediating apical transport is still very controversial. This could be partly due to the fact that in most studies exogenously expressed proteins were analysed. One has, therefore, examined the role of carbohydrate moieties in apical targeting of the endogenous secretory protein osteopontin in MDCK cells. It was found, however, that sorting of osteopontin does not require N-…
Coping with competition: neuroendocrine responses and cognitive variables.
2008
Confronting another individual or group motivated by the same goal is a very frequent situation in human communities that occurs in many other species. Competitive interactions emerge as critical situations that shed light on the effects and consequences of social stress on health. But more important than the situation itself is the way it is interpreted by the subject. This "appraisal" involves cognitive processes that contribute to explaining the neuroendocrine response to these interactions, helping to understanding the vulnerability or resistance to their effects. In this review, we defend the need to study human competition within the social stress framework, while maintaining an evolu…
Synaptobrevin cleavage by the tetanus toxin light chain is linked to the inhibition of exocytosis in chromaffin cells
1994
AbstractExocytosis of secretory granules by adrenal chromaffin cells is blocked by the tetanus toxin light chain in a zinc specific manner. Here we show that cellular synaptobrevin is almost completely degraded by the tetanus toxin light chain within 15 min. We used highly purified adrenal secretory granules to show that synaptobrevin, which can be cleaved by the tetanus toxin light chain, is localized in the vesicular membrane. Proteolysis of synaptobrevin in cells and in secretory granules is reversibly inhibited by the zinc chelating agent dipicolinic acid. Moreover, cleavage of synaptobrevin present in secretory granules by the tetanus toxin light chain is blocked by the zinc peptidase …
Cultured Ito cells of rat liver express the alpha 2-macroglobulin gene.
1987
Ito cells were isolated from rat liver and kept in culture for up to 13 days. The capability of the Ito cells to synthesize a2-macroglobulin was analyzed at different times after isolation and by pulse-chase experiments. Newly synthesized a2-macroglobulin was determined by immunoprecipitation followed by sodium dodecyl sulfate/ polyacrylamide gel electrophoresis and fluorography. a2-Macroglobulin synthesis was hardly detectable in Ito cells and their media 3 days after plating. However, 5 - 11 days after the isolation of the cells, increasing amounts of a2-macroglobulin were synthesized. The results of pulse-chase experiments performed on day 7 showed that radioactively labeled a2-macroglob…
Differential vesicular targeting and time course of synaptic secretion of the mammalian neurotrophins.
2005
Neurotrophins are a family of secreted neuronal survival and plasticity factors comprising NGF, BDNF, neurotrophin-3 (NT-3), and NT-4. Whereas synaptic secretion of BDNF has been described, the routes of intracellular targeting and secretion of NGF, NT-3, and NT-4 in neurons are poorly understood.To allow for a direct comparison of intracellular targeting and release properties, all four mammalian neurotrophins were expressed as green fluorescent protein fusion proteins in cultured rat hippocampal neurons. We show that BDNF and NT-3 are targeted more efficiently to dendritic secretory granules of the regulated pathway of secretion (BDNF, in 98% of cells; NT-3, 85%) than NGF (46%) and NT-4 (…
Estudio de anomalías meióticas y aneuploidías en pacientes con azoospermia secretora
2016
La contribución de anomalías meióticas a la infertilidad masculina humana ha sido reconocida desde hace tiempo. Los errores meióticos ligados a los procesos de sinapsis, recombinación y reparación del ADN, interfieren en el proceso normal de la meiosis pudiendo dar lugar a una segregación anómala de los cromosomas homólogos (meiosis I) ó las cromátidas hermanas (meiosis II) y generar espermatozoides portadores de alteraciones cromosómicas numéricas (aneuploides o diploides). El objetivo principal de la presente tesis doctoral fue estudiar las diferencias en el proceso de la meiosis entre varones de fertilidad probada y varones infértiles con azoospermia secretora de origen idiopático, difer…