| Lab Members | Current Research Interest | Publications | Opportunities |

Dra. PILAR PEREZ. (Profesora de Investigación del CSIC).
Dr. PEDRO M. COLL. (Profesor Contratado Doctor).
Dra. BEATRIZ SANTOS. (Profesora Titular).
RAUL ALONSO VIANA. (Becario predoctoral).
MIGUEL ESTRAVIS SASTRE. (Becario predoctoral).
ELVIRA PORTALES. (Técnico de Laboratorio CSIC).
ROSA MARIA SÁNCHEZ VICENTE (Técnico de Laboratorio).

CURRENT RESEARCH INTEREST

A major challenge in the modern Biology is to understand how cellular components sense cell size, measure distances, and position at specific locations inside the cell, so that the cell establish distinct functional domains to generate polarized growth. Polarization is defined as the generation and maintenance of directional cellular organisation. Polarized cell growth is fundamental to morphogenesis and development of both unicellular and pluricellular organisms. Eukaryotic cell growth responds to signals of two types: (1) intrinsic signals generated within a particular cell, and (2) extrinsic signals provided by sources external to the cell such as diffusible hormones or growth factors, cell to cell contacts, or signals from the extracellular matrix. Therefore, polarization could be viewed as a response to specific external or internal cues. However, many cells polarize even when deprived of directional cues, choosing a random axis and committing to it. This ‘symmetry breaking’ is probably caused by positive feedback loops that generate differences in the local concentrations of polarity factors, so that stochastic fluctuations are amplified. In all cases, cells need to select growth sites and reorganize their cytoskeleton and growth machinery accordingly. Some of the major players involved in the selection and maintenance of sites for polarized growth, such as the Rho GTPases are conserved from yeast to mammals, suggesting that the basic mechanisms involved may have been conserved throughout evolution.

The fission yeast Schizosaccharomyces pombe provides an excellent model to study both modes of polarized cell growth: intrinsically established during vegetative growth and extrinsically determined during mating. Fission yeasts are simple rod-shaped cells that grow at the cell tips and divide by medial fission. Cytokinesis is very similar to that in animal cells. One feature that makes fission yeast so ideal for the studies on spatial control is that its shape, size and division habits are extremely reproducible. Therefore, it is possible to identify mutants that have aberrant cell shape, cell size or cell division patterns. The advantage of a sequenced genome, coupled with excellent genetics and cytology, makes fission yeast a potent system for addressing these important questions in cell biology.

The main goal of our laboratory is to study the role of the Rho GTPases in the establishment and maintenance of cell polarity and growth of S. pombe. All the research projects in the lab involve extensive genetic, molecular biology and protein biochemistry, directed toward understanding the structural, biochemical, and cell biological mechanisms that regulate the morphogenesis in S. pombe cells, specifically, the signal transduction pathways regulated by the Rho family of GTPases, which includes Cdc42 and Rho1 to Rho5. These proteins exist in all eukaryotic cells, from yeast to mammals, and through a series of complex biochemical networks, control some of the fundamental processes of cell biology common to all eukaryotes, including morphogenesis, polarity, movement, and cell division. As in other fungi, S. pombe morphogenesis is closely related to cell wall biosynthesis, and Rho GTPases are critical modulators of this process. They provide the coordinated regulation of cell wall biosynthetic enzymes and actin organisation, required to maintain cell integrity and polarised growth. Currently, our lab is specifically focused in the following research: