Phospholipase C-gamma1 is Required for the Activation of Store-operated Ca2+ Channels in Liver Cells
Overview
Authors
Affiliations
Repetitive hormone-induced changes in concentration of free cytoplasmic Ca2+ in hepatocytes require Ca2+ entry through receptor-activated Ca2+ channels and SOCs (store-operated Ca2+ channels). SOCs are activated by a decrease in Ca2+ concentration in the intracellular Ca2+ stores, but the molecular components and mechanisms are not well understood. Some studies with other cell types suggest that PLC-gamma (phospholipase C-gamma) is involved in the activation of receptor-activated Ca2+ channels and/or SOCs, independently of PLC-gamma-mediated generation of IP3 (inositol 1,4,5-trisphosphate). The nature of the Ca2+ channels regulated by PLC-gamma has not been defined clearly. The aim of the present study was to determine if PLC-gamma is required for the activation of SOCs in liver cells. Transfection of H4IIE cells derived from rat hepatocytes with siRNA (short interfering RNA) targeted to PLC-gamma1 caused a reduction (by approx. 70%) in the PLC-gamma1 protein expression, with maximal effect at 72-96 h. This was associated with a decrease (by approx. 60%) in the amplitude of the I(SOC) (store-operated Ca2+ current) developed in response to intracellular perfusion with either IP(3) or thapsigargin. Knockdown of STIM1 (stromal interaction molecule type 1) by siRNA also resulted in a significant reduction (approx. 80% at 72 h post-transfection) of the I(SOC) amplitude. Immunoprecipitation of PLC-gamma1 and STIM1, however, suggested that under the experimental conditions these proteins do not interact with each other. It is concluded that the PLC-gamma1 protein, independently of IP3 generation and STIM1, is required to couple endoplasmic reticulum Ca2+ release to the activation of SOCs in the plasma membrane of H4IIE liver cells.
Kusic D, Connolly J, Kainulainen H, Semenova E, Borisov O, Larin A Physiol Genomics. 2019; 52(1):35-46.
PMID: 31790338 PMC: 6985788. DOI: 10.1152/physiolgenomics.00103.2019.
Wang P, Wang S, Xiao L, Chen J, Wang J, Rao J Am J Physiol Cell Physiol. 2017; 312(4):C367-C375.
PMID: 28100486 PMC: 5407017. DOI: 10.1152/ajpcell.00330.2016.
Shrestha C, Tang Y, Fan H, Li L, Zeng Q, Pennypacker S Biomed Res Int. 2016; 2016:3062765.
PMID: 27340655 PMC: 4909930. DOI: 10.1155/2016/3062765.
Shi J, Miralles F, Birnbaumer L, Large W, Albert A FASEB J. 2015; 30(2):702-15.
PMID: 26467792 PMC: 4714548. DOI: 10.1096/fj.15-280271.
Draberova L, Bugajev V, Potuckova L, Halova I, Bambouskova M, Polakovicova I Mol Cell Biol. 2014; 34(23):4285-300.
PMID: 25246632 PMC: 4248753. DOI: 10.1128/MCB.00983-14.