Sugar Regulatory Networks

The Jang lab is interested in understanding the molecular mechanisms underlying sugar sensing and signal transduction in plants [1, 2]. In the early work, we showed that hexokinase is involved in sugar signal transduction [3]. We then showed that both hexokinase-dependent and hexokinase-independent sugar signal transduction mechanisms exist in plants [4]. We also helped to demonstrate that plant sugar response can be modulated by stress hormone, hence forging the concept of sugar-stress hormone crosstalk [5]. Later we found that sugar induced stress hormone accumulation is partly responsible for sugar-stress hormone crosstalk [6]. Based on the results of our transcriptome analyses, we proposed a complex sugar signaling network mediated by multiple signal transduction pathways [7].

Medabolic Response

To further decipher this network, we began to systematically characterize sugar responsive transcription factors for their roles in various sugar signaling mechanisms. We showed that sugar responsive AtbZIP1 could form a complex bZIP protein dimerization network that differentially regulates downstream sugar responsive genes [8].

hybrid screening

Figure 1. Using both and Bimolecular fluorescence Complementation (BiFC) (left panel), it was revealed that AtbZIP1 and 7 other AtbZIPs form an extensive protein-protein interacting network (right panel) in controlling the expression of downstream sugar responsive genes. With recent new findings on another group of sugar responsive transcription factors, our current research is focused on:

  1. The functional analysis of Arabidopsis thaliana Tandem Zinc Finger (TZF) genes.
  2. Revealing the role of AtTZFs in RNA regulation mediated by plant P-body and stress granule.

References

  1. Jang, J.-C., and Sheen, J. (1997). Sugar sensing in higher plants. Trends in Plant Science 2, 208-214
  2. Sheen, J., Zhou, L., and Jang, J.C. (1999). Sugars as signaling molecules. Curr Opin Plant Biol 2, 410-418
  3. Jang, J.C., Leon, P., Zhou, L., and Sheen, J. (1997). Hexokinase as a sugar sensor in higher plants. Plant Cell 9, 5-19.
  4. Xiao, W., Sheen, J., and Jang, J.C. (2000). The role of hexokinase in plant sugar signal transduction and growth and development. Plant Mol Biol 44, 451-461.
  5. Zhou, L., Jang, J.C., Jones, T.L., and Sheen, J. (1998). Glucose and ethylene signal transduction crosstalk revealed by an Arabidopsis glucose-insensitive mutant. Proc Natl Acad Sci U S A 95, 10294-10299.
  6. Price, J., Li, T.C., Kang, S.G., Na, J.K., and Jang, J.C. (2003). Mechanisms of glucose signaling during germination of Arabidopsis. Plant Physiol 132, 1424-1438.
  7. Price, J., Laxmi, A., St Martin, S.K., and Jang, J.C. (2004). Global transcription profiling reveals multiple sugar signal transduction mechanisms in Arabidopsis. Plant Cell 16, 2128-2150.
  8. Kang, S.G., Price, J., Lin, P.C., Hong, J.C., and Jang, J.C. (2010). The Arabidopsis bZIP1 Transcription Factor Is Involved in Sugar Signaling, Protein Networking, and DNA Binding. Mol Plant 3, 361-373.