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Cellular and Immunobiology
Published in Karl H. Pang, Nadir I. Osman, James W.F. Catto, Christopher R. Chapple, Basic Urological Sciences, 2021
Masood Moghul, Sarah McClelland, Prabhakar Rajan
Golgi apparatus receives proteins from the ER and packages them for exocytosis.Stored in vesicles until signals are received, triggering their transport to the cell membrane.Fusion of vesicle to the cell membrane triggered by SNARE proteins.Exocytosis may be calcium-dependent (regulated) (e.g., nerve cells) or -independent (unregulated).Exocytosis also expels messages outside the cell to communicate with the environment.
Introduction: Background Material
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The reverse of endocytosis is exocytosis, in which a membrane-bounded vesicle containing some molecules fuses with the cell membrane, thereby releasing the molecules into the extracellular space. Secretion of hormones and release of neurotransmitters (Section 6.1.2.2) is by exocytosis.
Neuronal Function
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
Synaptic transmission in mammals usually occurs via chemical neurotransmitters (Figure 4.12). The presynaptic terminal is depolarized by an action potential, which opens voltage-gated calcium channels; calcium ions flow into the presynaptic terminal and cause neurotransmitter vesicles to fuse with the presynaptic membrane. The neurotransmitter is thus released into the synaptic cleft by exocytosis; it diffuses across the synaptic cleft and binds to receptors on the postsynaptic membrane and alters its permeability. The receptors in the postsynaptic membrane may be either ion channels or coupled with G proteins, which activate a second messenger system.
Advance in placenta drug delivery: concern for placenta-originated disease therapy
Published in Drug Delivery, 2023
Miao Tang, Xiao Zhang, Weidong Fei, Yu Xin, Meng Zhang, Yao Yao, Yunchun Zhao, Caihong Zheng, Dongli Sun
Exocytosis is the process that transport vesicles release their contents into the extracellular matrix through fusion with the plasma membrane. After being ingested by cells, nanoparticles will undergo a series of pathways in the cell and eventually be transported out of the cell (Dahiya & Ganguli, 2019; Sakhtianchi et al., 2013). The transport of nanoparticles across placental tissue is mainly through exocytosis and can occur in two main ways (Figure 3D): (i) after endocytosis, nanoparticles are internalized into early endosomes. Early endosomes become mature and form into multivesicular bodies, then fuse with the plasma membrane and release nanoparticles from the trophoblast. Therefore, nanoparticles reach fetal circulation; (ii) early endosomes transport nanoparticles to lysosomes, and then exocytosis of lysosomes can also release the contents into the villus matrix and subsequently into fetal capillaries. From the mechanism of nanoplatform transferring out of the placenta, it can be seen that the construction of nanoplatforms that can achieve lysosomal escape can make nanoplatforms stay in the placental trophoblast cells for a longer time and reduce the amount of placental transmission.
Modulating insulin secretion and inflammation against sodium arsenite toxicity by levosimendan as a novel pancreatic islets’ protector
Published in Toxin Reviews, 2023
Marzieh Daniali, Mona Navaei-Nigjeh, Maryam Baeeri, Soheyl Mirzababaei, Mahdi Gholami, Mahban Rahimifard, Mohammad Abdollahi
Regarding the insulin secretion pathway, it should be noted that insulin is produced in the endoplasmic reticulum and stored and transported in vesicles. Insulin is released from β-cells by exocytosis involving the attachment of secretory vesicles to the plasma membrane by a group of proteins called SNARE. The interaction of these proteins with the plasma membrane forms a stable complex that prepares the membrane for attachment and fusion to the granule. The exocytosis of vesicles is also regulated by Ca2+ concentration. Some studies also showed that as insulin granules become acidic, structural changes occur in the SNARE protein, facilitating its attachment to the membrane. By acting on the insulin gene transcription promoter, NaAsO2 toxin causes the cell to lose sensitivity to extracellular glucose concentrations and alter the stability of insulin mRNA, which is typically affected by glucose concentrations (Meloni et al.2013).
The role of SCAMP5 in central nervous system diseases
Published in Neurological Research, 2022
Ye Chen, Jiali Fan, Dongqiong Xiao, Xihong Li
In mammals, neurons, endocrine cells and exocrine cells all secrete proteins along the secretory pathway [17]. Genetics and in vitro experiments have revealed the molecular mechanism of exocytosis from neurons and from endocrine and exocrine cells. Innate immunity and adaptive immunity are regulated by cytokines, especially cytokines secreted by macrophages [18,19]. The membrane transport process during exocytosis and endocytosis is regulated by the SCAMP E peptide [20]. Previous studies on SCAMPs have mostly focused on the regulation of exocytosis during LDCV secretion or TGN vesicle transport. For example, SCAMP1 can promote the expansion and closure of fusion pores and participate in the regulation of LDCV secretion [21,22]. SCAMP2 interacts with phospholipase D1 and phosphatidylinositol diphosphate (PIP2) through its E peptide to regulate the formation of fusion pores during LDCV exocytosis [23].