What is the mechanism of store-operated Ca 2+ entry?

1. What is the mechanism of store-operated Ca2+ entry?

2. Measuring [Ca2+]ER and ICRAC in single cells Miyawaki et al, 1999

3. The ER sensor for CRAC channel activation has low Ca2+ affinity Possible candidates: Low-affinity, high-capacity (calreticulin, BiP, etc) Low-affinity, multi-EF hand (CREC family: reticulocalbin, ERC-55, etc)

4. References Smani et al, 2004 Yao et al, 1999 But see: Scott et al, 2003 Bakowski et al, 2003 Ma et al, 2000 But see: Sugawara et al, 1997 Prakriya & Lewis, 2001

5. A recent “diffusible messenger” model for SOC activation Smani et al, 2004

6. The fingerprint of the CRAC channel is a definitive benchmark for evaluating putative CRAC channel genes

7. The family of mammalian TRP channels Clapham, 2003 TRPC1: Mori et al, 2002 (DT40 knockout, inconsistent phenotype) TRPC3: Philipp et al, 2003 (CRAC mutants, rescues TCR but not TG response) TRPV6: Yue et al, 2001 (pore properties don’t match completely) Cui et al, 2002 (dom negative suppression of Icrac)

9. Ca2+ signals in a positively selecting environment 5C.C7 B6 thymocytes in B10.BR slice Time compression: 80x, total time 60 min

10. Calcium signals during positive selection are oscillatory Positive selection Neglect

11. A reductionist approach to the functions of Ca2+ dynamics in T cells: The Ca2+ clamp Dolmetsch et al, 1998

12. Frequency selectivity of transcriptional activation and gene expression Dolmetsch et al, 1998

14. Ca2+ oscillations boost signaling efficiency [Ca] Dinterval vs. Tomida et al, 2003

15. Delayed phosphorylation and transport of NFAT underlies the signaling efficiency of Ca2+ pulses Tomida et al, 2003