| Autor: |
Cecilia Astigiano, Andrea Benzi, Maria Elena Laugieri, Francesco Piacente, Laura Sturla, Lucrezia Guida, Santina Bruzzone, Antonio De Flora |
| Jazyk: |
angličtina |
| Rok vydání: |
2022 |
| Předmět: |
|
| Zdroj: |
Cells, Vol 11, Iss 17, p 2637 (2022) |
| Druh dokumentu: |
article |
| ISSN: |
2073-4409 |
| DOI: |
10.3390/cells11172637 |
| Popis: |
ADP-ribosyl cyclases (ADPRCs) catalyze the synthesis of the Ca2+-active second messengers Cyclic ADP-ribose (cADPR) and ADP-ribose (ADPR) from NAD+ as well as nicotinic acid adenine dinucleotide phosphate (NAADP+) from NADP+. The best characterized ADPRC in mammals is CD38, a single-pass transmembrane protein with two opposite membrane orientations. The first identified form, type II CD38, is a glycosylated ectoenzyme, while type III CD38 has its active site in the cytosol. The ectoenzymatic nature of type II CD38 raised long ago the question of a topological paradox concerning the access of the intracellular NAD+ substrate to the extracellular active site and of extracellular cADPR product to its intracellular receptors, ryanodine (RyR) channels. Two different transporters, equilibrative connexin 43 (Cx43) hemichannels for NAD+ and concentrative nucleoside transporters (CNTs) for cADPR, proved to mediate cell-autonomous trafficking of both nucleotides. Here, we discussed how type II CD38, Cx43 and CNTs also play a role in mediating several paracrine processes where an ADPRC+ cell supplies a neighboring CNT-and RyR-expressing cell with cADPR. Recently, type II CD38 was shown to start an ectoenzymatic sequence of reactions from NAD+/ADPR to the strong immunosuppressant adenosine; this paracrine effect represents a major mechanism of acquired resistance of several tumors to immune checkpoint therapy. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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