Cytoplasmic vesicles

Chordate neurons (early Cambrian) As above plus first hydroxylations giving serotonin and dopamine iron/pterin chemistry in cytoplasm vesicle filled in centre of cell Recovery by amine oxidation (flavoenzymes)... 

The recovery of neurotransmitters from synaptic clefts and their storage in cytoplasmic vesicles is accomplished by the tandem actions of the secondary transporters in plasma and vesicular membranes 84 Packaging neurotransmitters into presynaptic vesicles is mediated by proton-coupled antiporters 86... 

The process of infection of lupine nodule cells by Rhizobia was examined by the thin-section electron microscopic technique, as well as the freeze-fracture technique. Different membranes such as infection thread membranes, peribacterioid membranes, plasma membranes, membranes of cytoplasmic vesicles, and membranes of the Golgi bodies and ER were stained with uranium-lead, silver, phosphotungstic acid, and ZIO (31). ZIO stained the membranes of the proximal face of the Golgi bodies and endoplasmic reticulum. ZIO staining has given good contrast in thick sections such as a cotyledon cell, a root cell, and an aleurone layer for ER, dictyosomes cisternae, mitochondria, and nuclear envelopes (17,32-37). 

Transcytosis (vesicular transport, C). When new vesicles are pinched off, substances dissolved in the extracellular fluid are engulfed, and then ferried through the cytoplasm, vesicles (phagosomes) undergo fusion with lysosomes to form phagolysosomes, and the transported substance is metabolized. Alternatively, the vesicle may fuse with the opposite cell membrane (cytopempsis). 

Similar rosette-structures have been detected on the P-fracture faces of membranes of cytoplasmic vesicles in Micrasterias.367 The freeze-fracture images obtained suggested that the rosette complexes are first assembled into cytoplasmic vesicles, and are subsequently incorporated into the plasma membrane by a process of vesicle fusion. This supports the evidence obtained by Kiermayer and Dobberstein,371,372 in Micrasterias, that the flat vesicles that contain the rosette complexes are formed by the Golgi apparatus. 

One of the most important effects of insulin is to increase glucose uptake by cells 373/389 The mechanism is thought to depend upon the transporter protein GLUT4, which is stored within the membranes of small cytoplasmic vesicles. Binding of insulin to its receptors induces movement of these vesicles to the plasma membrane where fusion with the plasma membrane makes the GLUT4 molecules available for glucose transport.390 Phosphatidylinositol 3-kinase also plays an important role. The PtdIns(3,4)P2 and PtdIns(3,4,5)P3 generated by this enzyme (Fig. 11-9)... 

Cells continuously secrete materials via small cytoplasmic vesicles, which in eukaryotes arise largely from the Golgi apparatus (pp. 425-427 Fig. 20-8). The vesicles of this constitutive pathway may have diameters of 50 nm. They carry phospholipids, proteins, and other constituents for incorporation into the plasma membrane of the cell.618 619 In addition, there are... 

Figuer 17.3 Tracking of labeled PEI/DNA complexes (green) in cells with labeled lysosomes (red). Each bar indicates 10 pm. Times post-transfection are as follows (A) two hours—clumps of PEI/DNA complexes are present on the plasma membrane, and lysosomes are scattered throughout the cytoplasm (B) three hours—PEI/DNA complexes are located in endocytotic vesicles and are somewhat surrounded by lysosomes. There is no overlap of PEI and lysosomal probes (C) five hours—PEI/DNA complexes have entered the nucleus (shown by arrow) while cytoplasmic vesicles containing PEI/DNA complexes still have not fused with lysosomes. (Reproduced with permission from Godbey el al., 2000a). (see Color Plate 12)... 

Within the cell, P-gp can be expressed in several organelles and as such can influence the cellular distribution of its substrates. Studies with tumor cells have shown P-gp expression on the cell surface, in cytoplasmic vesicles, in Golgi apparatus, and in the nuclear envelope (208,209). Within vesicles and in Golgi apparatus, P-gp acts to sequester compounds as the transport is directed within the vesicle. At the nuclear membrane, P-gp acts to restrict access of substrates to the nucleus by directing transport in a cytoplasmic direction. This subcellular localization of P-gp can be an important consideration for P-gp substrates with intracellular targets (208). 

Inulin synthesis in the tubers occurs in the vacuoles of storage parenchyma cells. Kaeser (1983) proposed a model for the transport of sucrose into the central vacuole that involves the formation of vesicles within the cytoplasm that contain sucrose and inulin synthesis enzymes. The vesicles transfer their contents into the vacuole via two possible mechanisms (1) the cytoplasmic vesicle fuses with the tonoplast and through pinocytosis releases its contents into the vacuole, or (2) vesicles originating from plasmalemma invaginations are tied off into the vacuole, resulting in... 

Fig. 5.6 Fluorescence microscopy illustrating binding of fluorescein-conjugated human epidermal growth factor (hEGF) to the cell membrane of a single MDA-MB-458 human breast cancer cell, followed by internalization into cytoplasmic vesicles,...

The process by which eukaryotic cells take up solutes and/or particles by enclosure in a portion of the plasma membrane to (temporarily) form cytoplasmic vesicles. 

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