Future Perspectives on SDS-FRL and Research in Cellulose Biosynthesis

The specific labeling of c-di-GMP-binding protein to a single row of cellulose-synthesizing TCs in the outer fractured membrane of A. xylinum should allow localization of other proteins in these complexes (Kimura et al., 2001). In the near future, it will be possible to localize crystallization proteins and pore 

The application of this technique will also probe the localization of other proteins which are hypothesized to be components of rosette TCs in plant cells (Doblin et al. 2002 Joshi et al. 2004), the membrane-anchored glucanase (Lane et al. 2001 Molhoj et al. 2001 Sato et al. 2001 Szyjanowicz et al. 2004 Rober et al. 2005), sucrose synthase (Amoret al. 1995 Salnikov et al. 2001), and callose synthase (Cui et al. 2001 Zonglie et al. 2001a, b). A number of these proteins are important for cellulose synthesis. Recently, an Arabidopsis mutant defective in the COBRA protein was isolated (Roudier et al. 2005). This mutant exhibits disorganization of the orientation of cellulose microfibrils and subsequent reduction of crystalline cellulose. It is suggested that the COBRA protein is a GPI-anchored protein localized on the plasma membrane. This means that 

COBRA protein is involved in the regulation of eellulose microfibril arrays and in the future it may be possible to determine the localization of this protein by SDS-FRL. 

Generally speaking, SDS-FRL is a superb technique to visualize the localization of any kind of protein that resides not only in the plasma membrane but also the membranes of cell organelles. The authors hope that SDS-FRL will be applied in different fields to imderstand the function of not only plant cells but also other organisms in general. 

This work was supported, in part by Welch Grant F-1217 and DOE Grant DE-FG-02 03ER15396 to RMB. 

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