Abstract
The Cf-4/Avr4-gene-for-gene pair of tomato and the pathogenic fungus Cladosporium fulvum, respectively, is responsible for an incompatible interaction between host and pathogen. The Cf-4 protein is a trans-membrane, receptor-like protein. Upon perception of the C. fulvum effector Avr4, its short intracellular domain which lacks a clear signaling signature, is thought to
participate in the initiation of a signal transduction cascade eventually leading to resistance. Interestingly, the cytoplasmic C-terminus of Cf-4 contains a putative YxxΦ motif (YpaW), which is a sorting signal that binds to clathrin-associated
proteins and therefore might serve as an endocytosis signal. By site-directed mutagenesis we show that the integrity of this motif is required for full functionality of the Cf-4 protein. The clathrin-associated proteins are so-called adaptor-protein (AP) complexes that mediate the recruitment of clathrin to
membranes, thereby initiating endocytosis, and bind to the sorting signal. This binding occurs through the medium subunit of the AP complex, referred to as μ-adaptin. Indeed, yeast two-hybrid studies revealed that the C-terminus of Cf-4 interacts with tomato μ-adaptins. Furthermore, silencing of genes encoding these μ-adaptins results in loss of full Cf-4-mediated HR and resistance to C. fulvum. These results suggest that endocytosis plays an important role in Cf-4-mediated resistance. Current investigations aim to further clarify the role of the putative endocytosis signal in Cf-4 function. Furthermore, we want to identify all tomato μ-adaptins and test them for interaction with Cf-4 in yeast two-hybrid screens. Interestingly, the Cf-2 and Cf-5 proteins appear to lack this sorting signal in their cytoplasmic part and
therefore these will be included as controls as they are expected not to interact with the adaptins.
participate in the initiation of a signal transduction cascade eventually leading to resistance. Interestingly, the cytoplasmic C-terminus of Cf-4 contains a putative YxxΦ motif (YpaW), which is a sorting signal that binds to clathrin-associated
proteins and therefore might serve as an endocytosis signal. By site-directed mutagenesis we show that the integrity of this motif is required for full functionality of the Cf-4 protein. The clathrin-associated proteins are so-called adaptor-protein (AP) complexes that mediate the recruitment of clathrin to
membranes, thereby initiating endocytosis, and bind to the sorting signal. This binding occurs through the medium subunit of the AP complex, referred to as μ-adaptin. Indeed, yeast two-hybrid studies revealed that the C-terminus of Cf-4 interacts with tomato μ-adaptins. Furthermore, silencing of genes encoding these μ-adaptins results in loss of full Cf-4-mediated HR and resistance to C. fulvum. These results suggest that endocytosis plays an important role in Cf-4-mediated resistance. Current investigations aim to further clarify the role of the putative endocytosis signal in Cf-4 function. Furthermore, we want to identify all tomato μ-adaptins and test them for interaction with Cf-4 in yeast two-hybrid screens. Interestingly, the Cf-2 and Cf-5 proteins appear to lack this sorting signal in their cytoplasmic part and
therefore these will be included as controls as they are expected not to interact with the adaptins.
| Original language | English |
|---|---|
| Title of host publication | ISMPMI International Congress abstracts, Quebec City, Canada, 19-23 July 2009 |
| Publisher | International Society for Molecular Plant-Microbe Interactions |
| Pages | 151 |
| Publication status | Published - 2009 |
| Event | XIV Congress on Molecular Plant-Microbe Interactions, Quebec City, Canada - Duration: 19 Jul 2009 → 23 Jul 2009 |
Conference
| Conference | XIV Congress on Molecular Plant-Microbe Interactions, Quebec City, Canada |
|---|---|
| Period | 19/07/09 → 23/07/09 |