Expression of Ca2+‐permeable two‐pore channels rescues NAADP signalling in TPC‐deficient cells

Abstract

The second messenger NAADP triggers Ca 2+ release from endo‐lysosomes. Although two‐pore channels (TPCs) have been proposed to be regulated by NAADP, recent studies have challenged this. By generating the first mouse line with demonstrable absence of both Tpcn1 and Tpcn2 expression (Tpcn1/2 −/− ) , we show that the loss of endogenous TPCs abolished NAADP‐dependent Ca 2+ responses as assessed by single‐cell Ca 2+ imaging or patch‐clamp of single endo‐lysosomes. In contrast, currents stimulated by PI(3,5)P 2 were only partially dependent on TPCs. In Tpcn1/2 −/− cells, NAADP sensitivity was restored by re‐expressing wild‐type TPCs, but not by mutant versions with impaired Ca 2+ ‐permeability, nor by TRPML1. Another mouse line formerly reported as TPC‐null likely expresses truncated TPCs, but we now show that these truncated proteins still support NAADP‐induced Ca 2+ release. High‐affinity [ 32 P]NAADP binding still occurs in Tpcn1/2 −/− tissue, suggesting that NAADP regulation is conferred by an accessory protein. Altogether, our data establish TPCs as Ca 2+ ‐permeable channels indispensable for NAADP signalling.

References 53

1. 1.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

2. 2.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

3. 3.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

4. 4.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

5. 5.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

6. 6.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

7. 7.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

8. 8.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

9. 9.

   This reference’s wording can’t be shown under the paper’s licence.

   Not in our library

10. 10.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

11. 11.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

12. 12.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

13. 13.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

14. 14.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

15. 15.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

16. 16.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

17. 17.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

18. 18.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

19. 19.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

20. 20.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

21. 21.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

22. 22.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

23. 23.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

24. 24.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

25. 25.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

26. 26.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

27. 27.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

28. 28.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

29. 29.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

30. 30.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

31. 31.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

32. 32.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

33. 33.
    Purified TPC Isoforms Form NAADP Receptors with Distinct Roles for Ca2+ Signaling and Endolysosomal Trafficking · 2010

    No notice
34. 34.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

35. 35.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

36. 36.
    NAADP Activates Two-Pore Channels on T Cell Cytolytic Granules to Stimulate Exocytosis and Killing · 2012

    No notice
37. 37.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

38. 38.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

39. 39.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

40. 40.

    This reference’s wording can’t be shown under the paper’s licence.

    Not in our library

Cited by papers we hold 4

• Lysosomal Biology and Function: Modern View of Cellular Debris Bin · 2020
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• Agonist-mediated switching of ion selectivity in TPC2 differentially promotes lysosomal function · 2020
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• IP3 Receptor-Mediated Calcium Signaling and Its Role in Autophagy in Cancer · 2017
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• Intracellular sphingosine releases calcium from lysosomes · 2015
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