News about non-secretory exocytosis: mechanisms, properties, and functions

Abstract

The fusion by exocytosis of many vesicles to the plasma membrane induces the discharge to the extracellular space of their abundant luminal cargoes. Other exocytic vesicles, however, do not contain cargoes, and thus, their fusion is not followed by secretion. Therefore, two distinct processes of exocytosis exist, one secretory and the other non-secretory. The present review deals with the knowledge of non-secretory exocytosis developed during recent years. Among such developments are the dual generation of the exocytic vesicles, initially released either from the trans-Golgi network or by endocytosis; their traffic with activation of receptors, channels, pumps, and transporters; the identification of their tethering and soluble N-ethylmaleimide-sensitive factor attachment protein receptor complexes that govern membrane fusions; the growth of axons and the membrane repair. Examples of potential relevance of these processes for pathology and medicine are also reported. The developments presented here offer interesting chances for future progress in the field.

Enhancement of Anticancer Efficacy and Tumor Penetration of Sorafenib by Ionic Liquids

“…The intracellular amount of SRF in 4T1 cells decreased during the incubation with fresh media, which indicated that SRF was continuously expelled to the outside of the cells via exocytosis (Figure 2C). [ 22 ] Compared with cells exposed to SRF alone, CAGE‐exposed cells exhibited increased amounts of SRF remaining inside 4T1 cells, which suggests that exocytosis of SRF was decreased in the CAGE group. In particular, at the 30 and 60 min time points, exocytosis of SRF by 4T1 cells was significantly different between the two groups (Figure 2C).…”

How Filopodia Respond to Calcium in the Absence of a Calcium-binding Structural Protein: They Use Rapid Transit

“…Ca 2+ replenishment caused an increase in uptake (Figure 3B), indicating the restoration of the exchangeable compartment, however. A large pool of non-secretory exocytotic vesicles is present in the cell, that can serve as a reserve pool of membrane for increasing the capacity of this compartment (see for review, (D’Alessandro and Meldolesi, 2019)).…”

Polymer Pro-Drug Nanoparticles for Sustained Release of Cytotoxic Drugs Evaluated in Patient-Derived Glioblastoma Cell Lines and In Situ Gelling Formulations

“…NPs can be released from cells via exocytosis, which is distinguished by two main mechanisms: regulated exocytosis and constitutive exocytosis. Regulated exocytosis occurs when the contents of an intracellular vacuole are secreted from the cell in response to a specific signal, whereas constitutive exocytosis does not require a signal to secrete the macromolecules [ 11 , 12 ]. Cell internalisation and exocytosis pathways are of importance when considering the design and application of drug-loaded nanocarriers [ 13 ], and repeated endocytic and exocytic processes might be exploited by appropriately-designed NPs to enable ‘hopping’ of the carriers through multiple cell layers in order to enhance penetration through brain parenchyma.…”