| Autor: |
Sesorova IS; Department of Anatomy, Ivanovo State Medical Academy, Ivanovo, Russia., Karelina NR; Department of Anatomy, Saint Petersburg State Paediatric Medical University, St. Petersburg, Russia., Kazakova TE; Department of Anatomy, Ivanovo State Medical Academy, Ivanovo, Russia., Parashuraman S; Institute of Protein Biochemistry, Consiglio Nazionale Delle Ricerche (CNR-IBP), Naples, Italy., Zdorikova MA; Department of Anatomy, Ivanovo State Medical Academy, Ivanovo, Russia., Dimov ID; The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy., Seliverstova EV; Laboratory of Renal Physiology, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Torez Avenue, 44, 194223, St. Petersburg, Russia., Beznoussenko GV; The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy. galina.beznusenko@ifom.eu., Mironov AA; The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy. alexandre.mironov@ifom.eu. |
| Abstrakt: |
In spite of tremendous progress in deciphering the molecular mechanisms involved in intracellular transport in cell culture and in the test tube, many aspects of this process in situ remain unclear. Here, we examined lipid transcytosis in enterocytes in adult rats. Apical clathrin-coated buds and the ER exit sites were not found. After starvation, the Golgi complex was in a non-transporting state and contained many vesicles, but no intercisternal connections and typical the cis-most and the trans-most cisternae. Following the addition of the lipids in the form of chyme, pre-chylomicrons (pre-ChMs) were initially found in the tubules of the smooth SER attached to the basolateral plasmalemma below the belt composed of adhesive junctions (AJ) and always connected with other cisternae. However, the ER exit sites were still absent. Pre-ChMs moved into the cis-most cisterna and were concentrated in cisternal distensions at the trans-side of the Golgi complex. This induced attachment of the cis-most and the trans-most cisternae to the Golgi complex. Post-Golgi carriers fused with the basolateral plasmalemma and delivered ChMs outside. Overloading of enterocytes with lipids resulted in an accumulation of lipid droplets, an increase of the diameter of ChMs, and shift of the Golgi complex to the transporting state with the formation of intercisternal connections, attachment of the cis-most and the trans-most cisternae and disappearance of vesicles. These data are discussed from the functional point of view. In spite of tremendous progress in deciphering the molecular mechanisms involved in intracellular transport in cell culture and in the test tube, many aspects of this process in situ remain unclear. Here, we examined lipid transcytosis in enterocytes in adult rats. Apical clathrin-coated buds and the ER exit sites were not found. After starvation, the Golgi complex was in a non-transporting state and contained many vesicles, but no intercisternal connections and typical the cis-most and the trans-most cisternae. Following the addition of the lipids in the form of chyme, pre-chylomicrons (pre-ChMs) were initially found in the tubules of the smooth SER attached to the basolateral plasmalemma below the belt composed of adhesive junctions (AJ) and always connected with other cisternae. However, the ER exit sites were still absent. Pre-ChMs moved into the cis-most cisterna and were concentrated in cisternal distensions at the trans-side of the Golgi complex. This induced attachment of the cis-most and the trans-most cisternae to the Golgi complex. Post-Golgi carriers fused with the basolateral plasmalemma and delivered ChMs outside. Overloading of enterocytes with lipids resulted in an accumulation of lipid droplets, an increase of the diameter of ChMs, and shift of the Golgi complex to the transporting state with the formation of intercisternal connections, attachment of the cis-most and the trans-most cisternae and disappearance of vesicles. These data are discussed from the functional point of view. |
