Differential pathways for calcium influx activated by concanavalin A and CD3 stimulation in Jurkat T cells.
Sustained increase in [Ca(2+)](c) (Δ[Ca(2+)](c)) is a critical early signal from T-cell receptor (TCR/CD3). In general, Ca(2+)-release activated Ca(2+) channels (CRAC) are responsible for the Ca(2+) influx and Δ[Ca(2+)](c) after TCR/CD3 stimulation. However, T cells also express Ca(2+)-permeable nonselective cation channels such as TRPM2 and TRPC. Gd(3+) is a relatively selective blocker for CRAC at micromolar concentrations. Here, Jurkat T cells were used to investigate the Gd(3+)-resistant Ca(2+) influx (Δ[Ca(2+)](c,Gd)) induced by concanavalin A (ConA, 1 μg/ml), a widely used mitogenic agent for T cells, or by anti-CD3 Ab (αCD3). αCD3-induced Δ[Ca(2+)](c) was partly (~60%) inhibited by 1 μM Gd(3+) while thapsigargin-induced Δ[Ca(2+)] was almost completely abolished. ConA-induced Δ[Ca(2+)] was mostly inhibited by 1 μM Gd(3+) during the early phase (<30 s of ConA application) and became resistant during the late phase (>2 min). Induction of Δ[Ca(2+)](c,Gd) by αCD3 and ConA was inhibited by 2-aminoethoxydiphenyl borate (2-APB) and by N-(p-amylcinnamoyl) anthranilic acid, indicating that TRPM2 and TRPC are involved in this process. Treatment with Pyr-3, a TRPC3-specific inhibitor, potently suppressed Δ[Ca(2+)](c,Gd) by αCD3 (IC(50), 0.16 μM). Patch clamp experiments demonstrated that the TRPM2 channels were activated by ConA, and the TRPC-like channels were activated by αCD3. Our present study suggests that TRPM2 and TRPC3 are activated by ConA and TCR/CD3, respectively, in Jurkat T cells and are responsible for the induction of Δ[Ca(2+)](c,Gd).
Department of Physiology, Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul, 110-799, Republic of Korea.
Bo
B
Pang
Dong Hoon
DH
Shin
Kyung Sun
KS
Park
Yun Jeong
YJ
Huh
Joohan
J
Woo
Yin-Hua
YH
Zhang
Tong Mook
TM
Kang
Ki-Young
KY
Lee
Sung Joon
SJ
Kim
D017252:CD3 Complex / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects* / Q000502:physiology; D003208:Concanavalin A / Q000494:pharmacology*; D055724:Electrophysiological Phenomena; D006801:Humans; D019169:Jurkat Cells; D018408:Patch-Clamp Techniques; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism*; D050052:TRPC Cation Channels / Q000502:physiology; D050053:TRPM Cation Channels / Q000502:physiology; D013696:Temperature
D017252:CD3 Complex; D050052:TRPC Cation Channels; C104603:TRPC3 cation channel; D050053:TRPM Cation Channels; C121934:TRPM2 protein, human; D003208:Concanavalin A; D002118:Calcium