Canonical Transient Receptor Potential Channel 2 (TRPC2) as a Major Regulator of Calcium Homeostasis in Rat Thyroid FRTL-5 Cells: Importance of kinase C δ (PKCδ) and stromal interaction molecule 2 (STIM2)

A1 Originalartikel i en vetenskaplig tidskrift (referentgranskad)


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Publikationens författare: Sukumaran P, Löf C, Kemppainen K, Kankaanpää P, Pulli I, Näsman J, Viitanen T, Törnquist K
Förläggare: AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Publiceringsår: 2012
Tidskrift: Journal of Biological Chemistry
Tidskriftsakronym: J BIOL CHEM
Volym: 287
Nummer: 53
Artikelns första sida, sidnummer: 44345
Artikelns sista sida, sidnummer: 44360
Antal sidor: 16
ISSN: 0021-9258


Abstrakt

Mammalian non-selective transient receptor potential cation channels (TRPCs) are important in the regulation of cellular calcium homeostasis. In thyroid cells, including rat thyroid FRTL-5 cells, calcium regulates a multitude of processes. RT-PCR screening of FRTL-5 cells revealed the presence of TRPC2 channels only. Knockdown of TRPC2 using shRNA (shTRPC2) resulted in decreased ATP-evoked calcium peak amplitude and inward current. In calcium-free buffer, there was no difference in the ATP-evoked calcium peak amplitude between control cells and shTRPC2 cells. Store-operated calcium entry was indistinguishable between the two cell lines. Basal calcium entry was enhanced in shTRPC2 cells, whereas the level of PKC beta 1 andPKC delta, the activity of sarco/endoplasmic reticulum Ca2+-ATPase, and the calcium content in the endoplasmic reticulum were decreased. Stromal interaction molecule (STIM) 2, but not STIM1, was arranged in puncta in resting shTRPC2 cells but not in control cells. Phosphorylation site Orai1 S27A/S30A mutant and non-functional Orai1 R91W attenuated basal calcium entry in shTRPC2 cells. Knockdown of PKC delta with siRNA increased STIM2 punctum formation and enhanced basal calcium entry but decreased sarco/endoplasmic reticulum Ca2+-ATPase activity in wild-type cells. Transfection of a truncated, non-conducting mutant of TRPC2 evoked similar results. Thus, TRPC2 functions as a major regulator of calcium homeostasis in rat thyroid cells.

Senast uppdaterad 2020-19-01 vid 04:02