- Open Access
Quantitative Characterization of Budding Yeast Polarization at the Mesoscale
PRX Life 4, 023033 – Published 29 June, 2026
DOI: https://doi.org/10.1103/gp4c-y48t
Abstract
Cellular symmetry breaking or polarization is a key process that underlies many types of cellular behavior like division, migration, and differentiation. In budding yeast, polarization is required for bud site selection. Polarization of key regulator Cdc42 has been molecularly dissected for decades, yet current data provide insufficient constraints to quantitatively differentiate between pattern-forming mechanisms and models. Here we present a phenomenological description of polarization in terms of physical characteristics using live cell microscopy and quantitative analysis. We identify multiple phases of Cdc42 polarization and derive mesoscale observables that describe each phase, yielding a basal framework to systematically characterize symmetry-breaking phenotypes. We then apply this description to two case studies in which the wildtype polarity network is perturbed: a small perturbation after eliminating spatial cue communication and a larger perturbation involving removal of near-essential scaffold Bem1. This confirms the applicability of the framework in nonwildtype contexts while revealing differences between genetic backgrounds. Finally, we study the dynamics of other polarizing components by extending our analysis to the Gic2 PBD domain, a Cdc42-GTP biosensor, and to polarisome component Spa2, highlighting variation in spot dynamics between protein species while also showing similarities to Cdc42. Our approach enables standardized comparison of polarization between diverse molecular backgrounds at the mesoscale and helps constrain future modeling efforts.
Physics Subject Headings (PhySH)
Article Text
Supplemental Material
References (84)
- Y. M. Yamashita, H. Yuan, J. Cheng, and A. J. Hunt, Polarity in stem cell division: Asymmetric stem cell division in tissue homeostasis, Cold Spring Harbor Perspect. Biol. 2, a001313 (2010).
- W.-J. Rappel and L. Edelstein-Keshet, Mechanisms of cell polarization, Curr. Opin. Syst. Biol. 3, 43 (2017).
- J. P. Campanale, T. Y. Sun, and D. J. Montell, Development and dynamics of cell polarity at a glance, J. Cell Sci. 130, 1201 (2017).
- A. Asnacios and O. Hamant, The mechanics behind cell polarity, Trends Cell Biol. 22, 584 (2012).
- F. Peglion and N. W. Goehring, Switching states: Dynamic remodelling of polarity complexes as a toolkit for cell polarization, Curr. Opin. Cell Biol. 60, 121 (2019).
- S. Bera and D. Loeffler, Cell polarity: Cell type-specific regulators, common pathways, and polarized vesicle transport, Leukemia 39, 1558 (2025).
- J. Chant and J. R. Pringle, Patterns of bud-site selection in the yeast Saccharomyces cerevisiae., J. Cell Biol. 129, 751 (1995).
- H.-O. Park and E. Bi, Central roles of small GTPases in the development of cell polarity in yeast and beyond, Microbiol. Mol. Biol. Rev. 71, 48 (2007).
- B. D. Slaughter, S. E. Smith, and R. Li, Symmetry breaking in the life cycle of the budding yeast, Cold Spring Harbor Perspect. Biol. 1, a003384 (2009).
- K. E. Miller, P. J. Kang, and H.-O. Park, Regulation of Cdc42 for polarized growth in budding yeast, Microbial Cell 7, 175 (2020).
- B. Klünder, T. Freisinger, R. Wedlich-Söldner, and E. Frey, GDI-mediated cell polarization in yeast provides precise spatial and temporal control of Cdc42 signaling, PLoS Comput. Biol. 9, e1003396 (2013).
- B. Woods, H. Lai, C.-F. Wu, T. R. Zyla, N. S. Savage, and D. J. Lew, Parallel actin-independent recycling pathways polarize Cdc42 in budding yeast, Curr. Biol. 26, 2114 (2016).
- D. I. Johnson and J. R. Pringle, Molecular characterization of CDC42, a Saccharomyces cerevisiae gene involved in the development of cell polarity, J. Cell Biol. 111, 143 (1990).
- J.-g. Chiou, K. D. Moran, and D. J. Lew, How cells determine the number of polarity sites, eLife 10, e58768 (2021).
- K. Witte, D. Strickland, and M. Glotzer, Cell cycle entry triggers a switch between two modes of Cdc42 activation during yeast polarization, eLife 6, e26722 (2017).
- A. B. Goryachev and A. V. Pokhilko, Dynamics of Cdc42 network embodies a Turing-type mechanism of yeast cell polarity, FEBS Lett. 582, 1437 (2008).
- F. Brauns, L. Iñigo de la Cruz, W. K.-G. Daalman, I. de Bruin, J. Halatek, L. Laan, and E. Frey, Redundancy and the role of protein copy numbers in the cell polarization machinery of budding yeast, Nat. Commun. 14, 6504 (2023).
- Y. Liu, J. Xie, H.-O. Park, and W.-C. Lo, Mathematical modeling of cell polarity establishment of budding yeast, Commun. Appl Math. Comput. 6, 218 (2024).
- S. Ory and S. Gasman, Rho GTPases and exocytosis: What are the molecular links? Semin. Cell Dev. Biol. 22, 27 (2011).
- Y. Xie and Y. Miao, Polarisome assembly mediates actin remodeling during polarized yeast and fungal growth, J. Cell Sci. 134, jcs247916 (2021).
- J.-G. Chiou, S. A. Ramirez, T. C. Elston, T. P. Witelski, D. G. Schaeffer, and D. J. Lew, Principles that govern competition or co-existence in Rho-GTPase driven polarization, PLoS Comput. Biol. 14, e1006095 (2018).
- A. B. Goryachev and M. Leda, Many roads to symmetry breaking: Molecular mechanisms and theoretical models of yeast cell polarity, Mol. Biol. Cell 28, 370 (2017).
- L. Regueira and L. Marcon, The network basis of pattern formation: A topological atlas of multifunctional Turing networks, bioRxiv (2025), doi: https://doi.org/10.1101/2025.01.27.634997.
- E. T. Diepeveen, L. I. de la Cruz, and L. Laan, Evolutionary dynamics in the fungal polarization network, a mechanistic perspective, Biophys. Rev. 9, 375 (2017).
- E. T. Diepeveen, T. Gehrmann, V. Pourquié, T. Abeel, and L. Laan, Patterns of conservation and diversification in the fungal polarization network, Genome Biol. Evol. 10, 1765 (2018).
- G. Liu, M. Y. J. Yong, M. Yurieva, K. G. Srinivasan, J. Liu, J. S. Y. Lim, M. Poidinger, G. D. Wright, F. Zolezzi, H. Choi, N. Pavelka, and G. Rancati, Gene essentiality is a quantitative property linked to cellular evolvability, Cell 163, 1388 (2015).
- L. Laan, J. H. Koschwanez, and A. W. Murray, Evolutionary adaptation after crippling cell polarization follows reproducible trajectories, eLife 4, e09638 (2015).
- M. M. Glazenburg and L. Laan, Complexity and self-organization in the evolution of cell polarization, J. Cell Sci. 136, jcs259639 (2023).
- See Supplemental Material at http://link.aps.org/supplemental/10.1103/gp4c-y48t for yeast strains and construction methods, details of image preprocessing and analysis, imaging controls and Supplemental Videos, which includes Refs. [27, 30, 31, 57, 58, 81, 82, 83].
- F. O. Bendezú, V. Vincenzetti, D. Vavylonis, R. Wyss, H. Vogel, and S. G. Martin, Spontaneous Cdc42 polarization independent of GDI-mediated extraction and actin-based trafficking, PLoS Biol. 13, e1002097 (2015).
- N. Dietler, M. Minder, V. Gligorovski, A. M. Economou, D. A. H. L. Joly, A. Sadeghi, C. H. M. Chan, M. Koziński, M. Weigert, A.-F. Bitbol, and S. J. Rahi, A convolutional neural network segments yeast microscopy images with high accuracy, Nat. Commun. 11, 5723 (2020).
- A. S. Howell, M. Jin, C.-F. Wu, T. R. Zyla, T. C. Elston, and D. J. Lew, Negative feedback enhances robustness in the yeast polarity establishment circuit, Cell 149, 322 (2012).
- C.-C. Kuo, N. S. Savage, H. Chen, C.-F. Wu, T. R. Zyla, and D. J. Lew, Inhibitory GEF phosphorylation provides negative feedback in the yeast polarity circuit, Curr. Biol. 24, 753 (2014).
- M. E. Lee, W.-C. Lo, K. E. Miller, C.-S. Chou, and H.-O. Park, Regulation of Cdc42 polarization by the Rsr1 GTPase and Rga1, a Cdc42 GTPase-activating protein, in budding yeast, J. Cell Sci. 128, 2106 (2015).
- L. Ni and M. Snyder, A genomic study of the bipolar bud site selection pattern inSaccharomyces cerevisiae, Mol. Biol. Cell 12, 2147 (2001).
- J. Chant and I. Herskowitz, Genetic control of bud site selection in yeast by a set of gene products that constitute a morphogenetic pathway, Cell 65, 1203 (1991).
- C.-F. Wu, N. S. Savage, and D. J. Lew, Interaction between bud-site selection and polarity-establishment machineries in budding yeast, Phil. Trans. R. Soc. B 368, 20130006 (2013).
- S. G. Martin, Spontaneous cell polarization: Feedback control of Cdc42 GTPase breaks cellular symmetry, BioEssays 37, 1193 (2015).
- J. E. Irazoqui, A. S. Gladfelter, and D. J. Lew, Scaffold-mediated symmetry breaking by Cdc42p, Nat. Cell Biol. 5, 1062 (2003).
- P. J. Kang, A. Sanson, B. Lee, and H.-O. Park, A GDP/GTP exchange factor involved in linking a spatial landmark to cell polarity, Science 292, 1376 (2001).
- K. G. Kozminski, L. Beven, E. Angerman, A. H. Y. Tong, C. Boone, and H.-O. Park, Interaction between a Ras and a Rho GTPase couples selection of a growth site to the development of cell polarity in yeast, Mol. Biol. Cell 14, 4958 (2003).
- H.-O. Park, E. Bi, J. R. Pringle, and I. Herskowitz, Two active states of the Ras-related Bud1/Rsr1 protein bind to different effectors to determine yeast cell polarity, Proc. Natl. Acad. Sci. USA 94, 4463 (1997).
- P. J. Kang, L. Béven, S. Hariharan, and H.-O. Park, The Rsr1/Bud1 GTPase interacts with itself and the Cdc42 GTPase during bud-site selection and polarity establishment in budding yeast, Mol. Biol. Cell 21, 3007 (2010).
- S. E. Smith, B. Rubinstein, I. Mendes Pinto, B. D. Slaughter, J. R. Unruh, and R. Li, Independence of symmetry breaking on Bem1-mediated autocatalytic activation of Cdc42, J. Cell Biol. 202, 1091 (2013).
- E. M. Ozbudak, A. Becskei, and A. van Oudenaarden, A system of counteracting feedback loops regulates Cdc42p activity during spontaneous cell polarization, Dev. Cell 9, 565 (2005).
- S. Grinhagens, A. Dünkler, Y. Wu, L. Rieger, P. Brenner, T. Gronemeyer, M. A. Mulaw, and N. Johnsson, A time-resolved interaction analysis of Bem1 reconstructs the flow of Cdc42 during polar growth, Life Sci. Alliance 3, e202000813 (2020).
- L. Kozubowski, K. Saito, J. M. Johnson, A. S. Howell, T. R. Zyla, and D. J. Lew, Symmetry-breaking polarization driven by a Cdc42p GEF-PAK complex, Curr. Biol. 18, 1719 (2008).
- R. Li and R. Wedlich-Soldner, Bem1 complexes and the complexity of yeast cell polarization, Curr. Biol. 19, R194 (2009).
- A.-C. Butty, N. Perrinjaquet, A. Petit, M. Jaquenoud, J. E. Segall, K. Hofmann, C. Zwahlen, and M. Peter, A positive feedback loop stabilizes the guanine-nucleotide exchange factor Cdc24 at sites of polarization, EMBO J. 21, 1565 (2002).
- J. Chenevert, K. Corrado, A. Bender, J. Pringle, and I. Herskowitz, A yeast gene (BEM1) necessary for cell polarization whose product contains two SH3 domains, Nature (London) 356, 77 (1992).
- S. Basu, B. González, B. Li, G. Kimble, K. G. Kozminski, and P. J. Cullen, Functions for Cdc42p BEM adaptors in regulating a differentiation-type MAP kinase pathway, Mol. Biol. Cell 31, 491 (2020).
- M. Morawska and H. D. Ulrich, An expanded tool kit for the auxin-inducible degron system in budding yeast, Yeast 30, 341 (2013).
- A. Papagiannakis, J. J. de Jonge, Z. Zhang, and M. Heinemann, Quantitative characterization of the auxin-inducible degron: A guide for dynamic protein depletion in single yeast cells, Sci. Rep. 7, 4704 (2017).
- C.-F. Wu and D. J. Lew, Beyond symmetry-breaking: Competition and negative feedback in GTPase regulation, Trends Cell Biol. 23, 476 (2013).
- G.-C. Chen, Y.-J. Kim, and C. S. M. Chan, The Cdc42 GTPase-associated proteins Gic1 and Gic2 are required for polarized cell growth in Saccharomyces cerevisiae, Genes Dev. 11, 2958 (1997).
- P. J. Kang, K. E. Miller, J. Guegueniat, L. Beven, and H.-O. Park, The shared role of the Rsr1 GTPase and Gic1/Gic2 in Cdc42 polarization, Mol. Biol. Cell 29, 2359 (2018).
- S. Okada, M. E. Lee, E. Bi, and H.-O. Park, Probing Cdc42 polarization dynamics in budding yeast using a biosensor, in Methods in Enzymology, Enzymes as Sensors Vol. 589, edited by R. B. Thompson and C. A. Fierke (Academic Press, San Diego, CA, 2017), Chap. 6, pp. 171–204.
- S. Okada, M. Leda, J. Hanna, N. S. Savage, E. Bi, and A. B. Goryachev, Daughter cell identity emerges from the interplay of Cdc42, septins, and exocytosis, Dev. Cell 26, 148 (2013).
- Y.-J. Sheu, B. Santos, N. Fortin, C. Costigan, and M. Snyder, Spa2p interacts with cell polarity proteins and signaling components involved in yeast cell morphogenesis, Mol. Cell. Biol. 18, 4053 (1998).
- Y.-J. Sheu, Y. Barral, and M. Snyder, Polarized growth controls cell shape and bipolar bud site selection in Saccharomyces cerevisiae, Mol. Cell. Biol. 20, 5235 (2000).
- B. D. Atkins, S. Yoshida, K. Saito, C.-F. Wu, D. J. Lew, and D. Pellman, Inhibition of Cdc42 during mitotic exit is required for cytokinesis, J. Cell Biol. 202, 231 (2013).
- J. Chollet, A. Dünkler, A. Bäuerle, L. Vivero-Pol, M. A. Mulaw, T. Gronemeyer, and N. Johnsson, Cdc24 interacts with septins to create a positive feedback loop during bud site assembly in yeast, J. Cell Sci. 133, jcs240283 (2020).
- J. M. Dyer, N. S. Savage, M. Jin, T. R. Zyla, T. C. Elston, and D. J. Lew, Tracking shallow chemical gradients by actin-driven wandering of the polarization site, Curr. Biol. 23, 32 (2013).
- J. B. Kelley, G. Dixit, J. B. Sheetz, S. P. Venkatapurapu, T. C. Elston, and H. G. Dohlman, RGS proteins and septins cooperate to promote chemotropism by regulating polar cap mobility, Curr. Biol. 25, 275 (2015).
- D. Ghose and D. Lew, Mechanistic insights into actin-driven polarity site movement in yeast, Mol. Biol. Cell 31, 1085 (2020).
- P. J. Kang, R. Mullner, K. Lian, and H.-O. Park, Cdc42 couples septin recruitment to the axial landmark assembly via Axl2 in budding yeast, J. Cell Sci. 137, jcs261080 (2024).
- L. Clay, F. Caudron, A. Denoth-Lippuner, B. Boettcher, S. Buvelot Frei, E. L. Snapp, and Y. Barral, A sphingolipid-dependent diffusion barrier confines ER stress to the yeast mother cell, eLife 3, e01883 (2014).
- S. E. Campos, J. A. Avelar-Rivas, E. Garay, A. Juárez-Reyes, and A. DeLuna, Genomewide mechanisms of chronological longevity by dietary restriction in budding yeast, Aging Cell 17, e12749 (2018).
- C.-L. Chen and N. Perrimon, Proximity-dependent labeling methods for proteomic profiling in living cells, WIREs Dev. Biol. 6, e272 (2017).
- I. V. Kukhtevich, N. Lohrberg, F. Padovani, R. Schneider, and K. M. Schmoller, Cell size sets the diameter of the budding yeast contractile ring, Nat. Commun. 11, 2952 (2020).
- A. A. Almaghasilah, Automated and high-precision computational approaches to understanding complex biological systems, Ph.D. thesis, University of Maine, 2025.
- T. D. P. Brunet, Local ontology: Reconciling processualism and new mechanism, Eur. J. Philos. Sci. 14, 28 (2024).
- J. S. North, C. K. Wikle, and E. M. Schliep, A review of data-driven discovery for dynamic systems, Int. Stat. Rev. 91, 464 (2023).
- A. W. McClure, C.-F. Wu, S. A. Johnson, and D. J. Lew, Imaging polarization in budding yeast, in Methods in Molecular Biology, edited by T. Jin and D. Hereld (Humana Press, New York, 2016), Vol. 1407, pp. 13–29.
- C.-F. Wu, J.-G. Chiou, M. Minakova, B. Woods, D. Tsygankov, T. R. Zyla, N. S. Savage, T. C. Elston, and D. J. Lew, Role of competition between polarity sites in establishing a unique front, eLife 4, e11611 (2015).
- J. Meca, A. Massoni-Laporte, D. Martinez, E. Sartorel, A. Loquet, B. Habenstein, and D. McCusker, Avidity-driven polarity establishment via multivalent lipid–GTPase module interactions, EMBO J. 38, EMBJ201899652 (2019).
- K. Pombo-García, O. Adame-Arana, C. Martin-Lemaitre, F. Jülicher, and A. Honigmann, Membrane prewetting by condensates promotes tight-junction belt formation, Nature (London) 632, 647 (2024).
- D. Zwicker, O. W. Paulin, and C. ter Burg, Physics of droplet regulation in biological cells, Rep. Prog. Phys. 88, 116601 (2025).
- R. M. Garner, A. T. Molines, J. A. Theriot, and F. Chang, Vast heterogeneity in cytoplasmic diffusion rates revealed by nanorheology and doppelgänger simulations, Biophys. J. 122, 767 (2023).
- J. Han and K. Burgess, Fluorescent indicators for intracellular pH, Chem. Rev. 110, 2709 (2010).
- M. Davis, Application note: Nikon NIS-Elements Denoise.ai software: Utilizing deep learning to denoise confocal data, https://www.microscope.healthcare.nikon.com/en_AOM/resources/application-notes/nikon-nis-elements-denoise-ai-software-utilizing-deep-learning-to-denoise-confocal-data (2019).
- P. Randazzo, N. X. Bennis, J.-M. Daran, and P. Daran-Lapujade, gEL DNA: A cloning- and polymerase chain reaction–free method for CRISPR-based multiplexed genome editing, CRISPR J. 4, 896 (2021).
- G. I. Mendoza-Ochoa, J. D. Barrass, B. R. Terlouw, I. E. Maudlin, S. de Lucas, E. Sani, V. Aslanzadeh, J. A. Reid, and J. D. Beggs, A fast and tuneable auxin-inducible degron for depletion of target proteins in budding yeast, Yeast 36, 75 (2019).
- M. M. Glazenburg, E. Geurken, and L. Laan, Data belonging to publication ‘Quantitative characterization of budding yeast polarization at the mesoscale', 4TU.ResearchData (2026), https://doi.org/10.4121/90dc93d5-445f-463d-854e-70f43607ab01.