Stewart and Pitt Research Groups
sjp24 The ISZB meeting 2014 was a huge success and we would like to thank the organisers for putting together such an exciting programme.
Dr Samantha Pitt gave a talk entitled “The role of zinc in cardiac excitation-contraction coupling” and would like to thank ISZB for being selected as an awardee of an early career speaker prize at this meeting.
Dr Alan Stewart also presented his work on “Structural and biochemical characterization of zinc binding to serum albumin”.
Mant thanks to Tenovus Scotland for supporting our research. Dr Samantha Pitt and her team have just received a small grant to examine a new role for zinc in regulating cardiac sarcoplasmic reticulum calcium release.
Biochemical Society
9-10th October 2014
A Biochemical Society Focused Meeting
The aim of this meeting is to cover advances and controversies relating to intracellular Ca2+ channel function and dysfunction. Sessions will be led by early career scientists in order to engage “The next generation” of Ca2+ signallers. The meeting will cover contemporary developments in Ca2+ signalling mediated by the three main classes of intracellular Ca2+ release channels sensitive to NAADP, IP3 and ryanodine.
14th-19th September 2014
Zinc has important functions in initiating and regulating signal transduction as well as injury cascades in many cell systems. Zinc dyshomeostasis has been linked to several diseases, including cancer, Alzheimer’s disease, epilepsy, stroke and diabetes. Nutritional zinc deficiency, found in both developed and in third world countries, is associated with abnormal brain development and impaired learning and memory, but also with diarrhea, growth retardation and immune deficiency. The 2014 meeting will provide a detailed update by young scientists and leaders in the field of zinc biology.
The paper is out
Samantha J Pitt, Andy KM Lam, Katja Rietdorf, Antony Galione, and Rebecca Sitsapesan (2014)
Sci Signal, 7(326):ra46.
NAADP potently triggers Ca(2+) release from acidic lysosomal and endolysosomal Ca(2+) stores. Human two-pore channels (TPC1 and TPC2), which are located on these stores, are involved in this process, but there is controversy over whether TPC1 and TPC2 constitute the Ca(2+) release channels. We therefore examined the single-channel properties of human TPC1 after reconstitution into bilayers of controlled composition. We found that TPC1 was permeable not only to Ca(2+) but also to monovalent cations and that permeability to protons was the highest (relative permeability sequence: H(+) >> K(+) > Na(+) >/= Ca(2+)). NAADP or Ca(2+) activated TPC1, and the presence of one of these ligands was required forchannel activation. The endolysosome-located lipid phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2] had no effect on TPC1 open probability but significantly increased the relative permeability of Na(+) to Ca(2+) and of H(+)to Ca(2+). Furthermore, our data showed that, although both TPC1 and TPC2 are stimulated by NAADP, these channels differ in ion selectivity and modulation by Ca(2+) and pH. We propose that NAADP triggers H(+) release from lysosomes and endolysomes through activation of TPC1, but that the Ca(2+)-releasing ability ofTPC1 will depend on the ionic composition of the acidic stores and may be influenced by other regulators that affect TPC1 ion permeation.
