Lock JT, Parker I, Smith IF. A comparison of fluorescent Ca²⁺ indicators for imaging local Ca²⁺ signals in cultured cells.
Cell Calcium 2015;
58:638-48. [PMID:
26572560 DOI:
10.1016/j.ceca.2015.10.003]
[Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 10/05/2015] [Accepted: 10/26/2015] [Indexed: 11/23/2022]
Abstract
Localized subcellular changes in Ca(2+) serve as important cellular signaling elements, regulating processes as diverse as neuronal excitability and gene expression. Studies of cellular Ca(2+) signaling have been greatly facilitated by the availability of fluorescent Ca(2+) indicators. The respective merits of different indicators to monitor bulk changes in cellular Ca(2+) levels have been widely evaluated, but a comprehensive comparison for their use in detecting and analyzing local, subcellular Ca(2+) signals is lacking. Here, we evaluated several fluorescent Ca(2+) indicators in the context of local Ca(2+) signals (puffs) evoked by inositol 1,4,5-trisphosphate (IP3) in cultured human neuroblastoma SH-SY5Y cells, using high-speed video-microscopy. Altogether, nine synthetic Ca(2+) dyes (Fluo-4, Fluo-8, Fluo-8 high affinity, Fluo-8 low affinity, Oregon Green BAPTA-1, Cal-520, Rhod-4, Asante Calcium Red, and X-Rhod-1) and three genetically-encoded Ca(2+)-indicators (GCaMP6-slow, -medium and -fast variants) were tested; criteria include the magnitude, kinetics, signal-to-noise ratio and detection efficiency of local Ca(2+) puffs. Among these, we conclude that Cal-520 is the optimal indicator for detecting and faithfully tracking local events; that Rhod-4 is the red-emitting indicator of choice; and that none of the GCaMP6 variants are well suited for imaging subcellular Ca(2+) signals.
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