The molecular basis for calcium release by NAADP
Lead Research Organisation:
University College London
Department Name: Neuroscience Physiology and Pharmacology
Abstract
All cells of the body are physically separated from their surrounding environment by a membrane. In order for cells to respond to factors in the blood (such as hormones) which normally can not pass through the membrane, special 'messenger' molecules are used that are generated inside the cell upon contact of the stimulus with the cell. One of these molecules, NAADP controls cell function by mediating changes in the concentration of calcium. These calcium changes are important for many processes including, for example, fertilisation. Understanding how NAADP increases calcium levels is important to understand how cells work but at present we do not know the identity of the protein or 'channel' that opens in response to NAADP to allow calcium levels to change. In this proposal, we will study a family of proteins that we know very little about but which our initial experiments suggest are the channels for NAADP. We will define their location within the cell, determine exactly how they respond to NAADP and whether they are needed for hormones which make NAADP to mediate changes in calcium. The results of our experiments will provide urgently needed information on how NAADP functions and experimental tools to further study the effects of NAADP.
Technical Summary
Cytosolic calcium ions form the basis of a ubiquitous signal transduction pathway that controls a huge number of physiological processes. Understanding how changes in cytosolic calcium occur in response to extracellular cues is crucial for understanding how calcium dependent events are regulated, and has major implications for the many diseases in which calcium signals are perturbed. Recent studies have established a new calcium signalling pathway regulated by the potent calcium mobilizing messenger NAADP. Unlike the 'traditional' messenger molecules, IP3 and cyclic ADP-ribose, NAADP mobilizes acidic stores of calcium. Moreover, NAADP has the unique ability to coordinate the activity of other intracellular calcium channels. However, despite the critical importance of NAADP in triggering agonist-evoked calcium signals, the molecular identity of the target channel has yet to be unequivocally defined. This paucity in information is substantially hampering efforts to characterize the physiological roles of NAADP. In this application, we will test whether the target channels for NAADP are a family of proteins that bear homology to voltage-sensitive calcium channels and which in animals are almost completely uncharacterised. Using a combination of molecular and cell biology approaches, and based on substantial preliminary data, we expect to localize the candidate channels to the endo-lysosomal system, demonstrate their sensitivity to NAADP and establish their contribution to physiologically relevant agonist-evoked calcium signals. Determining the molecular basis for NAADP action will represent a major breakthrough in the signal transduction field that will not only substantially further our understanding of how calcium signals are generated but also provide truly novel opportunities for future study of this ubiquitous signalling pathway.
Organisations
People |
ORCID iD |
| Sandip Patel (Principal Investigator) |
Publications
Brailoiu E
(2009)
Essential requirement for two-pore channel 1 in NAADP-mediated calcium signaling.
in The Journal of cell biology
Brailoiu E
(2010)
An ancestral deuterostome family of two-pore channels mediates nicotinic acid adenine dinucleotide phosphate-dependent calcium release from acidic organelles.
in The Journal of biological chemistry
Brailoiu E
(2010)
An NAADP-gated two-pore channel targeted to the plasma membrane uncouples triggering from amplifying Ca2+ signals.
in The Journal of biological chemistry
Brailoiu GC
(2010)
Acidic NAADP-sensitive calcium stores in the endothelium: agonist-specific recruitment and role in regulating blood pressure.
in The Journal of biological chemistry
Bruschini L
(2009)
Fully implantable Otologics MET Carina device for the treatment of sensorineural hearing loss. Preliminary surgical and clinical results.
in Acta otorhinolaryngologica Italica : organo ufficiale della Societa italiana di otorinolaringologia e chirurgia cervico-facciale
Burgoyne T
(2015)
Calcium signaling at ER membrane contact sites.
in Biochimica et biophysica acta
Cai X
(2015)
Insights into the early evolution of animal calcium signaling machinery: a unicellular point of view.
in Cell calcium
Cai X
(2010)
Degeneration of an intracellular ion channel in the primate lineage by relaxation of selective constraints.
in Molecular biology and evolution
Churamani D
(2012)
The signaling protein CD38 is essential for early embryonic development.
in The Journal of biological chemistry
Churamani D
(2012)
Domain assembly of NAADP-gated two-pore channels.
in The Biochemical journal
Churamani D
(2013)
The N-terminal region of two-pore channel 1 regulates trafficking and activation by NAADP.
in The Biochemical journal
Dickinson GD
(2010)
Deviant nicotinic acid adenine dinucleotide phosphate (NAADP)-mediated Ca2+ signaling upon lysosome proliferation.
in The Journal of biological chemistry
Fernández B
(2016)
Iron overload causes endolysosomal deficits modulated by NAADP-regulated 2-pore channels and RAB7A.
in Autophagy
Gómez-Suaga P
(2012)
Leucine-rich repeat kinase 2 regulates autophagy through a calcium-dependent pathway involving NAADP.
in Human molecular genetics
Gómez-Suaga P
(2012)
A link between LRRK2, autophagy and NAADP-mediated endolysosomal calcium signalling.
in Biochemical Society transactions
Hockey LN
(2015)
Dysregulation of lysosomal morphology by pathogenic LRRK2 is corrected by TPC2 inhibition.
in Journal of cell science
Hooper R
(2011)
Membrane topology of NAADP-sensitive two-pore channels and their regulation by N-linked glycosylation.
in The Journal of biological chemistry
Hooper R
(2012)
NAADP on target.
in Advances in experimental medicine and biology
Hooper R
(2015)
TPC1 Knockout Knocks Out TPC1.
in Molecular and cellular biology
Jha A
(2014)
Convergent regulation of the lysosomal two-pore channel-2 by Mg²?, NAADP, PI(3,5)P2 and multiple protein kinases.
in The EMBO journal
Kilpatrick B
(2017)
An Endosomal NAADP-Sensitive Two-Pore Ca 2+ Channel Regulates ER-Endosome Membrane Contact Sites to Control Growth Factor Signaling
in Cell Reports
Kilpatrick BS
(2013)
Direct mobilisation of lysosomal Ca2+ triggers complex Ca2+ signals.
in Journal of cell science
Kilpatrick BS
(2015)
Methods for monitoring lysosomal morphology.
in Methods in cell biology
Kiselyov KK
(2012)
The intracellular Ca²? channels of membrane traffic.
in Channels (Austin, Tex.)
Levine TP
(2016)
Signalling at membrane contact sites: two membranes come together to handle second messengers.
in Current opinion in cell biology
Lin-Moshier Y
(2014)
The Two-pore channel (TPC) interactome unmasks isoform-specific roles for TPCs in endolysosomal morphology and cell pigmentation.
in Proceedings of the National Academy of Sciences of the United States of America
Lin-Moshier Y
(2012)
Photoaffinity labeling of nicotinic acid adenine dinucleotide phosphate (NAADP) targets in mammalian cells.
in The Journal of biological chemistry
Love NR
(2015)
NAD kinase controls animal NADP biosynthesis and is modulated via evolutionarily divergent calmodulin-dependent mechanisms.
in Proceedings of the National Academy of Sciences of the United States of America
Marchant J
(2013)
Questioning Regulation of Two-Pore Channels by NAADP
in Messenger
Marchant JS
(2012)
The Molecular Basis for Ca2+ Signalling by NAADP: Two-Pore Channels in a Complex?
in Messenger (Los Angeles, Calif. : Print)
Marchant JS
(2015)
Two-pore channels at the intersection of endolysosomal membrane traffic.
in Biochemical Society transactions
Maricevic A
(2010)
Unusual "Traction" Exostosis of the Femoral Diaphysis With Sciatic Nerve Compression
in JCR: Journal of Clinical Rheumatology
Patel S
(2010)
Two-pore channels: Regulation by NAADP and customized roles in triggering calcium signals.
in Cell calcium
Patel S
(2011)
Acidic Ca(2+) stores come to the fore.
in Cell calcium
Patel S
(2011)
The endo-lysosomal system as an NAADP-sensitive acidic Ca(2+) store: role for the two-pore channels.
in Cell calcium
Patel S
(2017)
NAADP-evoked Ca2+ signals through two-pore channel-1 require arginine residues in the first S4-S5 linker.
in Cell calcium
Patel S
(2018)
Two-pore channels and disease.
in Biochimica et biophysica acta. Molecular cell research
Patel S
(2012)
Triggering of Ca2+ signals by NAADP-gated two-pore channels: a role for membrane contact sites?
in Biochemical Society transactions
Patel S
(2018)
Thinking through acidic Ca2+ stores.
in Science signaling
Patel S
(2010)
Acidic calcium stores open for business: expanding the potential for intracellular Ca2+ signaling.
in Trends in cell biology
Patel S
(2009)
In with the TRP channels: intracellular functions for TRPM1 and TRPM2.
in Science signaling
Patel S
(2015)
Evolution of acidic Ca²? stores and their resident Ca²?-permeable channels.
in Cell calcium
Patel S
(2015)
Function and dysfunction of two-pore channels.
in Science signaling
Patel S
(2018)
Two-pore channels open up.
in Nature
Penny C
(2014)
A computational model of lysosome-ER Ca2+ microdomains
in Journal of Cell Science
Penny CJ
(2016)
Isolated pores dissected from human two-pore channel 2 are functional.
in Scientific reports
Penny CJ
(2019)
Mining of Ebola virus entry inhibitors identifies approved drugs as two-pore channel pore blockers.
in Biochimica et biophysica acta. Molecular cell research
Penny CJ
(2015)
Coupling acidic organelles with the ER through Ca²? microdomains at membrane contact sites.
in Cell calcium
Penny CJ
(2014)
A "mix-and-match" approach to designing Ca(2+) microdomains at membrane-contact sites.
in Communicative & integrative biology
| Description | We have identified and characterized a new class of ion channels known as the two-pore channels (TPCs). Our findings indicate that these proteins are responsible for releasing calcium from acidic organelles such as lysosomes in response to the second messenger NAADP. This is a major breakthrough as a definitive molecular correlate for NAADP action was not known. TPCs are now being studied by many groups worldwide. |
| Exploitation Route | TPCs now present themselves as novel therapeutic targets. See outcomes from independent work funded by Parkinson's UK. |
| Sectors | Healthcare Pharmaceuticals and Medical Biotechnology |
| URL | http://jcb.rupress.org/content/186/2/164.2.full.pdf+html |
| Description | A role for a novel animal endo-lysosomal Ca2+/H+ exchanger in Ca2+ signalling and chemotaxis |
| Amount | £428,461 (GBP) |
| Funding ID | BB/K000942/1 |
| Organisation | Biotechnology and Biological Sciences Research Council (BBSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 01/2013 |
| End | 01/2016 |
| Description | Abnormal lysosomal calcium signalling in Parkinson's: Clues from lysosomal storage disorders |
| Amount | £34,798 (GBP) |
| Funding ID | K-1107 |
| Organisation | Parkinson's UK |
| Sector | Charity/Non Profit |
| Country | United Kingdom |
| Start | 05/2012 |
| End | 03/2014 |
| Description | Membrane contact sites between endolysosomes and the ER as novel hubs in Ca2+ signalling |
| Amount | £430,122 (GBP) |
| Funding ID | BB/N01524X/1 |
| Organisation | Biotechnology and Biological Sciences Research Council (BBSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 06/2016 |
| End | 06/2019 |
| Description | Mis-coordinated Ca2+ signalling in Parkinson's |
| Amount | £92,276 (GBP) |
| Organisation | Parkinson's UK |
| Sector | Charity/Non Profit |
| Country | United Kingdom |
| Start | 08/2013 |
| End | 09/2016 |
| Description | Targeting two-pore channel 2 in LRRK2-dependent Parkinson's disease |
| Amount | £34,798 (GBP) |
| Funding ID | K-1412 |
| Organisation | Parkinson's UK |
| Sector | Charity/Non Profit |
| Country | United Kingdom |
| Start | 01/2015 |
| End | 09/2015 |