Prof. Shaul Yalovsky
Ph.D.: The Hebrew University of Jerusalem, Israel, 1993
Phone: (Office) +972-3-640-5268
(Lab) +972-3-640-5269
(Fax) +972-3-640 6933
E-mail: shauly@tauex.tau.ac.il
Room#: Britannia 603
Member's portrait

Research Interests

 

The study of this lab is directed to understand cell polarity and how it affects development and growth of plants. Cell polarity is fundamental to living organisms. In plants, a unique mechanism links the polar transport of the hormone auxin with pattern formation. This feature makes plants a superior model system for studying how cell polarity is associated with developmental processes. Rho superfamily small GTPases are central regulators of cell polarity in eukaryotes. The function of Rho proteins requires their association with discrete domains in the plasma membrane where they orchestrate cytoskeleton organization vesicle trafficking, and local gradients of calcium ions and Reactive Oxygen Species (ROS). Plants have a single family of Rho proteins known as either Rho of Plants (ROPs) or RACs. Our research focuses on different aspects of ROP function in regulation of cell polarity, pattern formation and signal transduction processes.

To associate with the plasma membrane ROPs undergo posttranslational lipid modification in their C-terminal hypervariable domain. These modifications include prenylation, primarily by geranylgeranyl, and stable S -acylation by palmitic and stearic acids. In addition, transient S -acylation of two G-domain cysteines is required for partitioning of ROPs into lipid rafts and function in regulation of cell polarity. We are studying how different combinations of lipid modifications affect ROP targeting, partitioning into membrane microdomains, membrane and molecular dynamics and signaling.

ROPs are localized in the plasma membrane.
A transient S-acylation switch regulates ROP signaling in regulation of cell polarity. For the full details see Sorek et al. (2010) Current Biology.

We discovered a family of five ROP interacting proteins, which we call ICRs (Interactors of Constitutively active ROP). One member of this family, ICR1, functions in recruitment of PIN auxin efflux carriers to their polar domains in the plasma membrane. Expression studies show that ICR1 transcription is quickly induced by auxin but that it is repressed by a posttranscriptional mechanism at the site of local auxin maximum at the root tip. Our findings show that ICR1 is an auxin-modulated component linking ROP orchestrated cell polarity with auxin-regulated gene expression and responses. We are studying the molecular basis of ICR1 function and how its expression is regulated.

 
The Rho associate scaffold ICR1 is a coiled coil protein. For details see Lavy et al. (2007) Current Biology.
 

ICR1 expression pattern (left) and the local auxin maximum (right). For details see Hazak et al. (2010) PLoS Biology.

ROPs are implicated in diverse hormonal, biotic and abiotic stress signaling. We are employing different strategies to identify ROP signaling cascades.


Selected Publications

Articles

 

Nadav Sorek, Oshik Segev, Orit Gutman, Einat Bar, Sandra Richter, Limor Poraty, Joel A. Hirsch, Yoav I. Henis, Efraim Lewinsohn, Gerd Jürgens and Shaul Yalovsky , “ An S -acylation switch of conserved G-domain cysteines is required for polarity signaling by ROP GTPases”, Current Biology (2010) 20:914-920 (PubMed / Article)

 

Ora Hazak and Shaul Yalovsky , “ An auxin regulated positive feedback loop integrates Rho modulated cell polarity with pattern formation”, Plant Signaling and Behavior (2010) 5: 1-3. (PubMed / Article)

 

Nadav Sorek and Shaul Yalovsky , Analysis of protein S -acylation by gas chromatography–coupled mass spectrometry using purified proteins , Nature Protocols ( 2010) 5: 842-848 (PubMed / Article)

 

Ora Hazak, Daria Bloch, Limor Poraty, Hasana Sternberg, Jing Zhang, Jiri Friml and Shaul Yalovsky , “ A Rho Scaffold Integration of The Secretory System With Auxin Feedback and Transporters is Essential for Proper Auxin Distribution in Plants ”, PLoS Biology, (2010) 8: e1000282 (PubMed / Article)

 

Nadav Sorek and Shaul Yalovsky , Protein–lipid modifications and Targeting of ROP/RAC and heterotrimeric G proteins”, In, Shaul Yalovsky, Fratisek Baluska and Alan Jones, Eds., G Protein Signaling in Plants, (2009) pp.71-90), In series : Signaling and Communication in Plants Springer-Verlag, Berlin, ISBN: 978-3-642-03523-4, DOI: 10,1007/978-3-642-03524-1 (Book)

 

Nadav Sorek, Daria Bloch and Shaul Yalovsky, “Protein lipid modifications in signaling and subcellular targeting”, Current Opinion in Plant Biology (2009) 12: 714-720 (PubMed / Article)

 

Nir Ohad and Shaul Yalovsky , “Utilizing Bimolecular Fluorescence Complementation (BiFC) to Assay Protein-Protein Interaction in Plants”, In: Methods Plant Developmental Biology, Hennig, L. and Köhler, C. (Eds), In: Methods in Molecular Biology series (2009) Humana Press, New York (Book)

 

Keren Bracha-Drori, Keren Shichrur, Tsofnat Cohen Lubetzky and Shaul Yalovsky , “Functional analysis of Arabidopsis post-prenylation CaaX processing enzymes and their function in subcellular protein targeting”, Plant Physiology (2008) 148: 119-131 (PubMed / Article)

 

Shaul Yalovsky , Daria Bloch, Nadav Sorek and Benedikt Kost , “Regulation of membrane trafficking, cytoskeleton dynamics and cell polarity by ROP/RAC GTPases”, Plant Physiology (2008) 147: 1527-1543 (PubMed / Journal)

 

Oliver Batistič, Nadav Sorek, Stefanie Schültke, Shaul Yalovsky and Jörg Kudla , “Dual fatty acyl modification determines the localization and plasma membrane targeting of CBL/CIPK Ca 2+ signaling complexes”, The Plant Cell (2008) 20: 1346-1362 (PubMed / Article)

 

Katja Baerenfaller, Jonas Grossmann, Monica A. Grobei, Roger Hull, Matthias Hirsch-Hoffmann, Shaul Yalovsky , Philip Zimmermann, Ueli Grossniklaus, Wilhelm Gruissem and Sacha Baginsky , “ Genome-scale proteomics reveals new Arabidopsis thaliana gene models and proteome dynamics”, Science (2008), 320: 938-941 (PubMed / Article)

 

Daria Bloch, Ora Hazak, Meirav Lavy and Shaul Yalovsky , “A novel ROP/RAC GTPase effector integrates plant cell form and pattern formation”, Plant Signaling & Behavior (2008) 3: 41-43 (PubMed / Article)

 

Nir Ohad, Keren Shichrur and Shaul Yalovsky , “The analysis of protein-protein interactions in plants by Bimolecular Fluorescence Complementation (BiFC)”, Plant Physiology (2007) 145: 1090-1099 (PubMed / Article)

 

Meirav Lavy, Daria Bloch, Ora Hasak, Itai Gutman, Limor Poraty, Nadav Sorek, Hasana Sternberg, and Shaul Yalovsky , “ A novel ROP/RAC effector links cell polarity root meristem maintenance and vesicle trafficking ”, Current Biology (2007) 17: 947-952 (PubMed / Article)

 

Chang Liu, Jing Zhou, Keren Bracha-Drori, Shaul Yalovsky , Toshiro Ito, and Hao Yu, “Specification of Arabidopsis floral meristem identity by repressing flowering time genes”, Development (2007) 134: 1901-1910 (PubMed / Article)

 

Nadav Sorek, Limor Poraty, Hasana Sternberg, Enat Bar, Efraim Lewinsohn and Shaul Yalovsky , " Activation status coupled transient S -acylation determines membrane partitioning of a plant Rho-related GTPase ", Molecular and Cellular Biology (2007) 27:2144-2154 (PubMed / Article)

 

Lavy, M and Yalovsky, S. "Association of Arabidopsis type-II ROPs with the plasma membrane requires a conserved C-terminal sequence motif and a proximal polybasic domain", The Plant Journal (2006) 46: 934-947 (PubMed / Article)

 

Keren Schichrur and Shaul Yalovsky , "Turning on the switch - RhoGEFs in plants", Trends in Plant Sciences (2006) 11: 57-59 (PubMed / Article)

 

Daria Bloch, Meirav Lavy, Yael Efrat, Idan Efroni, Keren Bracha-Drori, Muhamad Abu-Abied, Einat Sadot and Shaul Yalovsky , " Ectopic expression of an activated RAC in Arabidopsis disrupts membrane cycling", Molecular Biology of the Cell (2005) 16: 1913-1927 (PubMed / Article)

 

Keren Bracha-Drori, Keren Shichrur, Aviva Katz, Moran Oliva, Ruthie Angelovici, Shaul Yalovsky and Nir Ohad , “Detection of protein-protein interaction in plants using YFP fluorescence complementation”, The Plant Journal (2004) 40: 419-427 (PubMed / Article)

 

Mark P. Running, Meirav Lavy, Hasana Sternberg, Arnaud Galichet, Wilhelm Gruissem, Sarah Hake, Naomi Ori, and Shaul Yalovsky , "Enlarged meristems and delayed growth in plp mutants result from lack of CaaX prenyltransferases", Proceedings of the National Academy of Sciences USA (2004) 101: 7815-7820 (PubMed / Article)

 

Lavy, M., Bracha-Drori, K., Sternberg, H. and Yalovsky, S. Cell-specific prenylation independent mechanism regulates targeting of type-II RACs.” The Plant Cell (2002), 14: 2431-2450 (PubMed / Article)

 

Bracha-Drori, K., Lavy, M. and Yalovsky, S. “The Arabidopsis AtSTE24 is a CaaX Protease with Broad Substrate Specificity.” Journal of Biological Chemistry (2002) 277: 29856-29864 (PubMed / Article)

 

Luan, S., Kudla, J., Manuel Rodriguez-Concepcion, M., Yalovsky, S. and Gruissem W. “CaMs and CBLs: Calcium Sensors for Specific Signal-Response Coupling in Plants.” The Plant Cell (2002) 14 Supplement: S389-400 (PubMed / Article)

 

Caldelari D., Sternberg, H., Rodriguez Concepcion, M., Gruissem, W. and Yalovsky, S. “Efficient prenylation by a plant geranylgeranyltransferase-I requires a functional CaaL box motif and a proximal polybasic domain.” Plant Physiology (2001) 126: 1416-1429 (PubMed / Article)

 

Rodriguez Concepcion, M., Toledo-Ortiz, G., Yalovsky, S. , Caldelari D. and Gruissem, W. “Carboxyl methylation of prenylated calmodulin CaM53 is required for efficient plasma membrane targeting of the protein.” The Plant Journal (2000) 24: 775-784 (PubMed / Article)

 

Yalovsky,S. , Rodriguez Concepcion, M., Bracha K., Toledo-Ortiz, G. and Gruissem, W. "Prenylation of the floral transcription factor APETALA1 modulates its function." The Plant Cell (2000) 12: 1257-1266 (PubMed / Article)

Yalovsky, S. , Kulukian A., Rodriguez Concepcion, M., Young, C.A. and Gruissem W. “Functional requirement of plant farnesyltransferase during development in Arabidopsis.” The Plant Cell (2000) 12: 1267-1278 (PubMed / Article)

 

Book

Shaul Yalovsky, Fratisek Baluska and Alan Jones , Eds., Integrated G Protein Signaling in Plants, 2009, In series : Signaling and Communication in Plants, Springer, Heidelberg, ISBN: 978-3-642-03523-4, DOI: 10,1007/978-3-642-03524-1 (Book)


Students and Lab Members

Present lab Members

Amir Akerman – Ph.D student

Email: akermanamir@gmail.com

Dr. Hasana Sternberg – senior research assistant

Email: hasana@post.tau.ac.il

       

Ora (Irena) Hazak – PhD student

Email: orel_hazak@yahoo.com

 

Sophie Tchuscha – M.SC student

Email: sophie.tc@gmail.com

Former Lab members

Dr. Keren Bracha-Drori – reseach specialist Clontech Inc. CA, USA

Dr. Meirav Lavy – postdoctoral fellow, UCSD, CA, USA

Dr. Daria Bloch – postdoctoral fellow, Tel Aviv University, Israel

Dr. Keren Shichrur – postdoctoral fellow, Tel Aviv University, Israel

Dr. Limor Poraty – research specialist, Evogen Inc., Rehovot, Israel

Dr. Nadav Sorek – postdoctoral fellow, UC Berekeley, CA, USA

Ms. Tsofnat Lubezky, technical specialist, Eldan Inc., Israel

Mr. Itay Gutman, PhD student, Weizmann Institute

Ms. Olga Dementiev, research specialist, Israel

Mr. Eran Kaufman