FIGURE 1.7. Comparison of the inhibitory effect of genistein on ROCE and SOCE endogenous to HEK cells, COS-7 cells, and mouse embryonic fibroblasts lacking the indicated members of the src-family of tyrosine kinases.

FIGURE 1.7

Comparison of the inhibitory effect of genistein on ROCE and SOCE endogenous to HEK cells, COS-7 cells, and mouse embryonic fibroblasts lacking the indicated members of the src-family of tyrosine kinases. In the experiments shown in this and the other figures, ROCE was assessed in cells expressing the indicated Gq-coupled GPCR in transient or stable form, loading the cells that had been plated on coverslips with fura2 and subjecting these cells to a Ca2+ mobilization protocol in which the PLC system was activated by the cognate receptor agonist (carbachol [CCh] for the M5 muscarinic receptor and arginine vasopressin [AVP] for the V1a vasopressin receptor) in the absence of external Ca2+. [Ca2+]i changes were then followed by video spectromicroscopy to record Ca2+ release from internal stores and allowing [Ca2+]i to return to near basal levels. At this point, Ca2+ was added to the external medium and influx of Ca2+ leading to increase in [Ca2+]i representing ROCE, was monitored for the indicated times. When drugs such as genistein or KB-R7943 (see below) were added, they were present through the first and second phases of the [Ca2+]i changes. Note that only the Ca2+ entry phases are shown. In none of the experiments shown in this or the other figures did the presence of tyrosine kinase or Na-Ca exchange inhibitors affect significantly the IP3- or thapsigargin-induced Ca2+ release from the endogenous stores. SOCE was assessed by substituting the GPCR agonist for thapsigargin. Gd3+ (5–10 μM) was added when TRPC-mediated ROCE was measured. At this concentration of Gd3+ TRPC3, 5, 6, and 7 mediated Ca2+ entry is unaffected, but endogenous ROCE is inhibited. Data on effects of genistein are either unpublished or adapted from Kawasaki et al. [80]

From: Chapter 1, The TRPC Family of Ion Channels: Relation to the TRP Superfamily and Role in Receptor- and Store-Operated Calcium Entry

Cover of TRP Ion Channel Function in Sensory Transduction and Cellular Signaling Cascades
TRP Ion Channel Function in Sensory Transduction and Cellular Signaling Cascades.
Liedtke WB, Heller S, editors.
Boca Raton (FL): CRC Press/Taylor & Francis; 2007.
Copyright © 2007, Taylor & Francis Group, LLC.

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