Venkata, B.P., and Schrick, K. 2006. START domains in lipid/sterol transfer and signaling in plants. In C. Benning and J. Ohlrogge (eds.) Current Advances in the Biochemistry and Cell Biology of Plant Lipids: Proceedings of the 17th International Symposium on Plant Lipids, Michigan State University, East Lansing, Michigan. ISPL2006, pp. 57-61.

Schrick, K., Nguyen, D., Karlowski, W.M., and Mayer, K.F.X. 2004. START lipid/sterol binding domains are amplified in plants and are predominately associated with homeodomain transcription factors. Genome Biology 5: R41.

Schrick, K., Fujioka, S., Takatsuto, S., Stierhof, Y.-D., Stransky, H., Yoshida, S., and Jürgens, G. 2004. A link between sterol biosynthesis, the cell wall and cellulose in Arabidopsis. Plant J. 38: 227-243.

Schrick, K., Mayer, U., Martin, G., Bellini, C., Kuhnt, C., Schmidt, J., and Jürgens, G. 2002. Interactions between sterol biosynthesis genes in embryonic development of Arabidopsis. Plant J. 31: 61-73.

Schrick, K., and Laux, T. 2001. Zygotic Embryogenesis: The formation of an embryo from a fertilized egg. In S.S. Bhojwani & W.Y. Soh (eds.) Current Trends in the Embryology of Angiosperms, Kluwer Academic Publishers, Dordrecht, pp. 249-277.

Schrick, K. 5 December 2000. Perspective: Plant developmental biologists show their colors: Toward a virtual understanding of green development. Science´s STKE 61: pe1.

Schrick, K., Mayer, U., Horrichs, A., Kuhnt, C., Bellini, C., Dangl, J., Schmidt, J., and Jürgens, G. 2000. FACKEL is a sterol C-14 reductase required for organized cell division and expansion in Arabidopsis embryogenesis. Genes Dev. 14: 1471-1485.

Kathrin Schrick’s research interests include: Sterol Biosynthesis and Signaling, Steroids, Lipids, Gene Expression, and Plant Development. The long-term goals of her lab are to elucidate the signaling roles of sterols in plant growth and development. A recent discovery was that sterol biosynthesis is crucial for cellulose synthesis. Sterol production may indicate the metabolic states of cells, which in turn are exploited to regulate developmental processes such as cell differentiation. Such a mechanism would ensure a proper sequence of events in controlling cell fate decisions during development.

The characterization of Arabidopsis patterning mutants first led to the hypothesis that sterols have signaling roles in plants. The mutants exhibit defects such as multiple meristems in both the embryo and seedling. The developmental defects are not rescued by exogenous application of brassinosteroids, which are the only steroid hormones identified from plants thus far. Moreover, while mutants affecting the brassinosteroid biosynthesis pathway show characteristic dwarf phenotypes, they do not exhibit patterning defects in embryogenesis. These observations indicate that steroid molecules in addition to brassinosteroids have roles in embryonic development.

The identification of sterol signals and their binding sites will be of key importance in the connection between sterol biosynthesis and signal transduction in plants. Candidate sterol-binding proteins in plants include transcription factors of the homeodomain class termed HD-START. Proteins of this family contain a DNA-binding domain, the homeodomain (HD), associated with a leucine zipper (ZLZ or ZIP) dimerization domain, and a lipid/sterol binding domain (START). The START domain from human StAR has been shown to bind sitosterol as well as cholesterol in vitro, consistent with the possibility that the START domains from plants also bind sterols.

The presence of START domains in transcription factors reveals a potential mechanism by which lipid/sterol ligands regulate gene transcription in plants. HD-START transcription factors are implicated cell differentiation during development: Several correspond to striking mutant phenotypes in Arabidopsis and have layer-specific expression patterns in both Arabidopsis and rice. It is postulated that the binding of ligands to the START domain of HD-START transcription factors functions to control cell differentiation in plants. Molecular, genetic, and proteomics approaches are being applied to investigate the role of START domains in plant development.