PUBLIC AFFAIRS

Calcium Signaling and Ion Channel Regulation: From Brain to Roots

Sheng Luan of the Department of Plant and Microbial Biology, University of California, Berkeley, spoke at a seminar sponsored by the ASPB Mid-Atlantic Section on

	Washington University Professor Ralph Quatrano (second from right), former ASPB president and former editor-in-chief of The Plant Cell, is reunited with individuals he mentored. Second from left is ASPB Executive Director Crispin Taylor, and Professor Heven Sze of the University of Maryland is at right. ASPB Public Affairs Director Brian Hyps is at left. Ralph presented a talk on “Physcomitrella: The System and Genome to Address Plant Functions” at the ASPB Mid-Atlantic Section’s annual spring meeting March 28.

March 27 at the University of Maryland. His talk addressed the CBL–CIPK calcium-signaling network in plants. Following is an abstract from his talk:

Almost all signal transduction processes in plants involve Ca2+ that serves as a vital second messenger. Understanding how Ca2+ mediates the cellular responses triggered by myriad environmental signals is one of the most important goals for plant biologists in the years to come.

Recent studies uncovered a new family of Ca2+ sensors (CBLs) that target a family of protein kinases (CIPKs), establishing a novel paradigm for Ca2+ signaling in plants (1–3). The calcium sensors and protein kinases are encoded by two multigene families. In Arabidopsis (with the smallest genome among flower plants), at least 10 CBLs and 25 CIPKs were identified. Each CBL interacts with a selected repertoire of CIPKs, and each CIPK interacts with one or more CBLs. Some CBLs have common CIPK targets, and some CIPKs share CBL regulatory proteins.

Such specific and overlapping schemes in the CBL–CIPK interaction suggest both specific and redundant functions among the members of the two gene families. Genetic analysis has begun to reveal the function of individual CBLs and CIPKs. Available results indicate that CBL–CIPK interactions form an extensive network that functions in a number of signaling pathways, including plant responses to abiotic stress, nutrition status, and abscisic acid (4–11). Such analysis, and analysis using other means such as RNAi approach (12), will place each CBL–CIPK complex into a functional context of signal transduction in plants.

References

1. Kudla et al. 1999. PNAS 96:4718.
2. Shi et al. 1999. Plant Cell 11:2393.
3. Luan et al. 2002. Plant Cell S14:s389.
4. Kim et al. 2003. Plant Cell 15:411.
5. Cheong et al. 2003. Plant Cell 15:1833–1845.
6. Pandey et al. 2004. Plant Cell 16:1912.
7. Li et al. 2006. PNAS 103:12625.
8. Lee et al. 2007. PNAS 104:15959.
9. Pandey et al. 2007. Cell Res. 17:411.
10. Cheong et al. 2007. Plant J. 52:223.
11. Kim et al. 2007. Plant J. 52:473.
12. Pandey et al. 2008. Mol. Plant 1:238.