PUBLICATION

Two-Pore Channel 2 activity is required for slow muscle cell-generated Ca2+ signaling during myogenesis in intact zebrafish

Authors
Kelu, J.J., Chan, H.L., Webb, S.E., Cheng, A.H., Ruas, M., Parrington, J., Galione, A., Miller, A.L.
ID
ZDB-PUB-151219-5
Date
2015
Source
The International journal of developmental biology   59: 313-325 (Journal)
Registered Authors
Galione, Antony, Miller, Andrew L., Webb, Sarah E.
Keywords
two-pore channel 2, Ca2+ signaling, slow muscle cell myogenesis, zebrafish, in vivo imaging
MeSH Terms
  • Animals
  • Animals, Genetically Modified
  • Calcium/metabolism*
  • Calcium Channels/genetics
  • Calcium Channels/metabolism*
  • Calcium Signaling/genetics*
  • Inositol 1,4,5-Trisphosphate Receptors/genetics
  • Inositol 1,4,5-Trisphosphate Receptors/metabolism
  • Lysosomes/metabolism
  • Muscle Development/genetics*
  • Muscle, Skeletal/metabolism*
  • Ryanodine Receptor Calcium Release Channel/genetics
  • Ryanodine Receptor Calcium Release Channel/metabolism
  • Zebrafish/metabolism
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed
26679948 Full text @ Int. J. Dev. Biol.
Abstract
We have recently characterized essential inositol 1,4,5-trisphosphate receptor (IP 3R) and ryanodine receptor (RyR)-mediated Ca (2+)signals generated during the differentiation of slow muscle cells (SMCs) in intact zebrafish embryos. Here, we show that the lysosomal two-pore channel 2 (TPC2) also plays a crucial role in generating, and perhaps triggering, these essential Ca (2+)signals, and thus contributes to the regulation of skeletal muscle myogenesis. We used a transgenic line of zebrafish that expresses the bioluminescent Ca (2+)reporter, aequorin, specifically in skeletal muscle, in conjunction with morpholino (MO)-based and pharmacological inhibition of TPC2, in both intact embryos and isolated SMCs. MO-based knock-down of TPC2 resulted in a dramatic attenuation of the Ca (2+)signals, whereas the introduction of TPCN2-MO and TPCN2 mRNA together partially rescued the Ca (2+)signaling signature. Embryos treated with trans-ned-19 or bafilomycin A1, a specific NAADP receptor inhibitor and vacuolar-type H (+)ATPase inhibitor, respectively, also displayed a similar disruption of SMC Ca (2+)signaling. TPC2 and lysosomes were shown via immunohistochemistry and confocal laser scanning microscopy to be localized in perinuclear and striated cytoplasmic domains of SMCs, coincident with patterns of IP 3R and RyR expression. These data together imply that TPC2-mediated Ca (2+)release from lysosomes acts upstream from RyR- and IP 3R-mediated Ca (2+)release, suggesting that the former might act as a sensitive trigger to initiate the SR-mediated Ca (2+)-induced-Ca (2+)-release essential for SMC myogenesis and function.
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