Carlos R. Vázquez de Aldana

Morphogenesis and cell separation in yeast and fungi

Our laboratory is interested in studying the regulation of cell separation in fungi and yeasts. The last step of the cell cycle is the individualization of the two newly formed cells and occurs by the controlled dissolution of the septum by the action of hydrolytic enzymes that degrade the components of the septum. Since cell separation occurs shortly after the septum has been synthesized, the temporal regulation of this process must be finely coordinated with the synthesis of the septum, to prevent cell lysis due to premature degradation of the septum. At the same time, in some yeasts there is also a spatial control of separation, since it occurs from the daughter cell. Temporal and spatial control of this process depend on several signaling pathways that coordinate it with other cell cycle events and ensure that the destruction of the septum is a process that occurs only once in the life of a cell, when it is a daughter cell. We use Schizosaccharomyces pombe and Candida albicans as model systems to study this process.

In the fission yeast Schizosaccharomyces pombe, we have have identified some of the proteins involved in the dissolution of the septum and the transcription factor that regulates their periodic expression in the M/G1 transition, named Ace2. We are interested in studying the regulation of Ace2 activity by the signaling pathways that control mitosis and cytokinesis, including the CDK activity (cyclin dependent kinase) and the SIN (similar to the MEN pathway that regulates exit from mitosis in S. cerevisiae) and MOR (similar to the RAM pathway that controls Ace2 and polarized growth) pathways.

C. albicans has the ability to grow in different morphologies, including yeast, pseudohyphae and hyphae, and this ability is considered an important virulence factor. This organism is an ideal system to study the regulation of separation, since filament formation leads to inhibition of separation to allow the formation of long filaments. In recent years, we have shown that inhibition of the separation depends on the specific modification of the septin ring in the hyphae. The septins are a family of conserved proteins in eukaryotic cells (except in plants) that play essential roles in cells, including the recruitment of other proteins to the septum region and the formation of diffusion barriers in this region. We are interested in studying the mechanisms that connect the septin ring dynamics with cell inhibition and the Ace2 transcription factor, and in analyzing the regulation of this process by the CDK activity and the RAM pathway.

Cell separation in C. albicans
In C. albicans, during yeast growth the RAM pathway (whose final effector is the Cbk1-Mob2 comlpex) is required for asymmetric accumulation of Ace2 in the nucleus of the daughter cell, where it activates the expression of genes required for separation. Induction of filament formation involves changes in septin ring dynamics that are necessary to inhibit cell separation of the hyphal compartments (upper photo). Some mutants activate cell separation in hyphae (lower).

Group members
Encarnación Dueñas Titulado Superior
Sara Orellana Titulado Superior
Ana Santos PhD Student
Belén Suarez Professor (USAL)
Francisco del Rey Full Professor Microbiology (USAL)
Carlos Rodríguez Research Scientist (CSIC)
Recent publications
Suárez, B., Alonso-Núñez, ML., Rey, F., McInerny, C., Vázquez de Aldana, C.R. (2015).
Regulation of Ace2-dependent genes requires components of the PBF complex in Schizosaccharomyces pombe.
Cell Cycle 14: 3124-3137
Calderón-Noreña, D., González-Novo, A., Orellana-Muñoz, S., Gutiérrez-Escribano, P., Arnáiz-Pita, Y., Dueñas-Santero., E., Suárez, B., Bougnoux. M., Rey, F. del., Sherlock, G., d’Enfert, C., Correa-Bordes, J., Vázquez de Aldana, C.R. (2015).
A single nucleotide polymorphism uncovers a novel function for the transcription factor Ace2 during Candida albicans hyphal development..
PLOS Genetics 11: e1005152.
Encinar del Dedo, J., Idrissi, F., Arnáiz-Pita, Y., James, M., Dueñas-Santero, M.E., Orellana-Muñoz, S., Rey, F. del, Sirotkin, V., Geli, M.I., Vázquez de Aldana, CR. (2014).
Eng2 is a component of a dynamic protein complex required for endocytic uptake in fission yeast.
Traffic 15: 1122–1142
Gutiérrez-Escribano, P., Zeidler, U., Suárez, B., Bachellier-Bassi, S., Clemente-Blanco, A., Bonhomme, J., Vázquez de Aldana, C.R., d’Enfert, C., Correa-Bordes, J. (2012).
The NDR/LATS Kinase Cbk1 Controls the Activity of the Transcriptional Regulator Bcr1 during Biofilm Formation in Candida albicans.
PLOS Pathogens 8: e1002683.
Gutiérrez-Escribano, P., González-Novo, A., Suárez, B., Li, C., Wang, Y., Vázquez de Aldana, C.R., Correa-Bordes, J. (2011).
Cdk-dependent phosphorylation of Mob2 is essential for hyphal development in Candida albicans.
Mol. Biol. Cell 22: 2458-2469
Research grants
MINECO BFU-2010-15884
MINECO BIO2015-70195-C2-1-R
Links of interest