Intracellular transport, organelle biogenesis and establishment of golgi identity: Impact of brefeldin a on the activity of lipid synthesizing enzymes

Concluding Step in Cell Restitution Cycle: ER Transport Vesicles with Sphingolipids in the Outer Leaflet of the Membrane Restore Lysosomes

“…Within the assigned categories of the vesicles directed from ER to Golgi, our studies documented structure and contents of apical and basolateral transport vesicles which revealed that their membrane assembly is dependent on the SphNH 2 -and Cer-synthesizing ER -constitutive enzymes providing SPhL core for GSL and SM assembled in Golgi [45] [47] [50] [53] [60]. The challenge confronted here was to identify membrane markers that differentiate between SM-containing basolateral and endosomal vesicles that with other membrane constituents co-determine their divergent destination sites.…”

“…Thus, from the outset of the coded metabolic conversions, the retention of the characteristic specificity of the cellular and organellar membranes defined by the protein and specific lipids, encrypt their paramount structural attributes that guard cells from untoward conversions [14]- [16] [20] [30]. The specific lipid environment that is repeatedly assembled for every integral membrane protein is not acquired at any time, or by chance, but reflects co-translational creation of the membrane for which the particular structure is essential [39]- [42] [45]- [50] [53] [60]. Bearing in mind the complexity of membrane receptors, their distinct positioning and multiple traversing in order to achieve competent form, the simplistic view of their incorporation into membrane after translation fails to explain the phenomenal fidelity of their placement within the specific membrane and delivery to the precisely assigned site [11] [68].…”

“…The example of such void is the interpretation of Toll-like receptors signal transduction as "promiscuous" due to binding reactivity with phosphatidylinositol phosphates (PIPs) and phosphatidylinositol bisphosphates (PIP2s) but "beneficial means of diversifying the subcellular sites of innate immune signal transduction" [5] [69]- [72]. In our view, established through examination of the vesicular specificity of cellular transport, the results provide exquisite example of the vesicles transporting specific TLRs to the apical and basolateral membrane armed with their specific destination markers in form of PIPs (PI3P and PI4P), respectively [40] [41] [50] [53] [60]. Moreover, the vesicles named endosomes are most likely the cell membrane fragments (autophagosomes) undergoing excision and on their way for lysosomal degradation.…”

“…ER-and Golgi-derived transport vesicles were generated in the presence of radiolabeled precursors according to procedure described previously [39] [60]. The ER or Golgi membranes, mixed with CC, ATP-generating system, UTP, CTP GTP, fatty acyl CoA and water soluble cold or radiolabeled lipids precursors, were incubated for 30 min at 37˚C, centrifuged over 0.3 M sucrose and treated with stripping buffer at 2˚C for 15 min followed by centrifugation at 10,000 xg for 10 min to separate transport vesicles from ER or Golgi membranes.…”

Role of Signal-Regulated Changes in Microtubule Stability Dynamics through <i>α</i>-Tubulin Phosphorylation on Ser/Tyr in Modulation of Salivary Gland Matrix Metalloproteinase-9 (MMP-9) Secretion in Response to <i>Porphyromonas gingivalis</i> and Ghrelin

“…An intact Golgi apparatus fraction of the salivary gland acinar cells was prepared essentially according to the previously described procedure [29]. The acinar cells were homogenized for 10 s at 600 rpm in 3 volumes of 50 mM Tris-HCl buffer, …”