생명과학과·I-Bio 특별세미나 안내

[Announcement on Life Sciences·I-Bio Special Seminar (3) ]
          
            
         ▶Subject: A mechanism for the localized Casparian strip formation in the endodermis
         
         ▶Speaker: Yuree Lee, Ph.D. (Junior Group Leader, Institute for Basic Science (IBS))
                 
         ▶Date: 13:00~14:00 /Dec./11(Thu)/2014
                
         ▶Place: Auditorium(1F), POSTECH Biotech Center
                
                 *Abctract
             Epithelial polarity is a fundamental feature of multi-cellular life, and model systems for animal epithelia have been intensely investigated for decades. Epithelial polarity is more complex than individual cell polarity and higher plants are the other relevant group of organisms to have independently achieved this. However, little is known about the mechanisms whereby diverse plant tissue layers establish and maintain differences between outer and inner cellular surfaces.
One tissue that displays all the hallmarks of an epithelium is the root endodermis that is an invariant feature of all vascular plants and fulfils a crucial barrier function, separating the apoplastic space of outer cell layers (connected to the soil) with the inner apoplastic space of the vascular bundles. In order to act as a barrier, endodermal cells secrete hydrophobic material in a highly localized and coordinated fashion and form "Casparian strips (CS)". The chemical composition of CS has been studied for many decades in various species, but it has remained a matter of debate, which in turn has confined further molecular analysis.
In this talk, I will present our findings that establish lignin as the chemical nature of the primary root-diffusion barrier in Arabidopsis and enable a mechanistic dissection of the formation of CS. In addition, I will talk about the mechanism how the precise localization of extracellular matrix and cell wall components is established at the CS: the Casparian strip, a lignin-based diffusion barrier, forms as a precise median ring by the concerted action of a specific, localized NADPH oxidase, brought into proximity of localized peroxidases through the action of Casparian strip domain proteins (CASPs). Our findings in Arabidopsis provide a simple mechanistic model of how plant cells regulate lignin formation with subcellular precision. I will also discuss about the speculation that scaffolding of NADPH oxidases to the downstream targets of the reactive oxygen species (ROS) might be a widespread mechanism to ensure specificity and subcellular precision of ROS action within the extracellular matrix

      ?▶Inquiry: Life Sciences Tel: 279-2721, 8181