Secretion machinery at the cell plasma membrane

Study on Improvement of Extracellular Production of Recombinant Thermobifida fusca Cutinase by Escherichia coli

“…Other researchers reported that recombinant proteins with a periplasmic secretory peptide such as PelB were translocated into periplasm after being synthesized. After cleavage of the PelB peptide, some of the proteins localized and accumulated in the periplasm, meanwhile other proteins passed through the outer membrane and then released into the culture medium by nonspecific leakage [12][13][14][15][16][17]. The reported mechanism accords with our previously experimental facts of PelB-fused T. fusca cutinase expressed in E. coli [11].…”

Identification of new structural elements within ‘porosomes’ of the exocrine pancreas: A detailed study using high-resolution electron microscopy

“…The central inner ring has a diameter of 25-30 nm, with a 20-25 nm central opening, similar to the ring formed when t-SNARE and v-SNARE in opposing bilayers (larger liposome-associated SNAREs) meet Cho et al, 2002a,b,c,d,e;Abu-Hamdah et al, 2004;Jeremic et al, 2004aJeremic et al, ,b, 2005Kelly et al, 2004;Taraska et al, 2003). Studies further demonstrate that during secretion, secretory vesicles swell, resulting in the generation of hydrostatic pressure inside the vesicle, which allows the contents of the vesicle to discharge to the outside of the cell through the circular SNARE complex channel at the porosome base, and through the porosome opening at the cell plasma membrane (Anderson, 2006a,b;Jena, 2002Jena, , 2005Jena, , 2007Jena, , 2009aJena, ,b, 2010Aravanis et al, 2003;Tojima et al, 2000;Thorn et al, 2004;Alvarez De Toledo et al, 1993;Wang et al, 2012;Cho et al, 2002d). Although major advancements have been made in our understanding of secretion from the exocrine pancreas, the detailed morphology of porosomes in the exocrine pancreas in situ remains to be further explored.…”

“…Until recently, it was commonly accepted that the final step in secretion is the total incorporation of secretory vesicle membrane into the cell plasma membrane leading to the release of intravesicular contents by diffusion, and the compensatory retrieval of excess membrane by endocytosis at a later time (Ichikawa, 1965;Ceccarelli et al, 1972;Dreifuss, 1975;Saras et al, 1981;Ryan et al, 1996;Valentijn et al, 1999;Zenisek et al, 2002;Heidelberger, 2001;Sudhof, 1995;Fischer von Mollard et al, 1994;Walch-Solimena et al, 1995). Studies within the past 20 years have finally revealed a completely different molecular mechanism of secretion and membrane fusion in cells Cho et al, 2002aCho et al, ,c,e, 2004Jena, 2002Jena, , 2004Jena, , 2005Jena, , 2007Jena, , 2008Jena, , 2009aJena, ,b, 2010Jena et al, 1997Jena et al, , 2003Jeremic et al, 2003Jeremic et al, , 2004aJeremic et al, ,b, 2005Jeremic et al, , 2006Clary et al, 1990;Söllner et al, 1993;Rothman and Söllner, 1997;Weber et al, 1988;Craciun, 2004;Jeftinija, 2006;Leabu, 2006;Anderson, 2006a,b). Monck and Fernandez (1996) suggested the existence of fusion pore at the cell plasma membrane, which became continuous with the secretory vesicle membrane after stimulation of secretion.…”

Altered osteogenic commitment of human mesenchymal stem cells by ERM protein-dependent modulation of cellular biomechanics

“…A strong membrane-cytoskeleton adhesion would maintain structural integrity of load-bearing cells (e.g., osteoblasts) subjected to multiple stress cycles (Sheetz et al, 2006). On the other hand, a relatively loose membrane attachment to actin cytoskeleton in hMSCs facilitates signaling through exo-and endocytosis and cross-membrane trafficking (Jena, 2007;Titushkin and Cho, 2006). Our laboratory has recently demonstrated and characterized the cytoskeleton-membrane adhesion using laser optical tweezers (LOT) to generate membrane tethers (Titushkin et al, 2010).…”