[Effects of panax quinquefolius saponin of stem and leaf on glucose-lipid metabolism and insulin signal transduction in insulin resistant model adipocytes].

Objective: To observe the effects of panax quinquefolius saponin (PQS) of stem and leaf on glucose-lipid metabolism and insulin signal transduction in the insulin resistant model of adipocytes.

Methods: The insulin resistant model of differentiated 3T3-L1 adipocytes was established in vitro with free fatty acid. After induction of insulin resistance, cells were treated with metformin or PQS for 2 days.

ERK binds, phosphorylates InsP3 type 1 receptor and regulates intracellular calcium dynamics in DT40 cells.

Modulation on the duration of intracellular Ca(2+) transients is essential for B-cell activation. We have previously shown that extracellular-signal-regulated kinase (ERK) can phosphorylate inositol 1,4,5-trisphosphate receptor type 1 (IP(3)R1) at serine 436 and regulate its calcium channel activity. Here we investigate the potential physiological interaction between ERK and IP(3)R1 using chicken DT40 B-cell line in which different mutants are expressed.

Inositol 1,4,5-trisphosphate receptor type 1 phosphorylation and regulation by extracellular signal-regulated kinase.

Type 1 inositol 1,4,5-trisphosphate receptor (IP(3)R1) is a widely expressed intracellular calcium-release channel found in many cell types. The operation of IP(3)R1 is regulated through phosphorylation by multiple protein kinases. Extracellular signal-regulated kinase (ERK) has been found involved in calcium signaling in distinct cell types, but the underlying mechanisms remain unclear.

Strontium promotes calcium oscillations in mouse meiotic oocytes and early embryos through InsP3 receptors, and requires activation of phospholipase and the synergistic action of InsP3.

Background: Sr2+ is the most efficient agent for mouse oocyte activation and functions by inducing Ca2+ oscillations. However, its specific mechanism of action remains unknown. Here we investigated the specificity and possible mechanism of Sr2+-induced Ca2+ oscillations in mouse oocytes and early embryos.