Functional analysis of the SYP1 syntaxin family

• Applicant: Professor Dr. Gerd Jürgens
• Subject Area: Plant Cell and Developmental Biology
• Term: from 2002 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5388416

Syntaxins are receptors on target membranes that mediate pathway-specific vesicle docking in intracellular trafficking. Among the 24 putative syntaxins of Arabidopsis, the 9 members of the SYP1 family display weak similarity to plasma membrane-associated syntaxins of other eukaryotes. Except for the cytokinesis-specific syntaxin KNOLLE (SYP111) and a putative orthologue of the plasma membrane-localised tobacco SYR1 (SYP121), nothing is known about SYP1 proteins. The aim of this project is to analyse all members of the SYP1 family. We will search for knockout mutants and examine their possible defects in intracellular trafficking. Expression and subcellular localisation of myc-tagged SYP1 proteins will be studied in transgenic plants. Myc-tagged SYP1 proteins will be expressed under the control of KNOLLE (and SYR1) cis-regulatory sequences to assess their functional specificity in terms of targeting to the cell plate (and plasma membrane) and ability to cross-complement knolle (and syr1) mutants. Using the cell cycle-regulated accumulation, targeting and function of KNOLLE protein as an assay system, we aim to identify functional domains of SYP1 proteins. To this end, chimaeric proteins consisting of varying proportions of KNOLLE and other SYP1 proteins will be analysed for targeting, stability and knolle rescuing activity.

• DFG Programme: Research Grants