Cell death is a natural part of the development of multicellular organisms and is central to their physiological and pathological states. However, the existence of regulated cell death in unicellular microorganisms, including eukaryotic and prokaryotic microbes, has been a topic of debate. One reason for the continued debate is the lack of obvious benefit from cell death in the context of a single cell. However, unicellularity is relative, as most of these microbes dwell in communities of varying complexities, often with complicated spatial organization. In these spatially organized microbial communities, such as yeast and bacterial colonies and biofilms growing on solid surfaces, cells differentiate into specialized types, and the whole community often behaves like a simple multicellular organism. As these communities develop and age, cell death appears to offer benefits to the community as a whole. This review explores the potential roles of cell death in spatially organized communities of yeasts and draws analogies to similar communities of bacteria. The natural dying processes in microbial cell communities are only partially understood and may result from suicidal death genes, (self-)sabotage (without death effectors), or from non-autonomous mechanisms driven by interactions with other differentiated cells. We focus on processes occurring during the stratification of yeast colonies, the formation of the extracellular matrix in biofilms, and discuss potential roles of cell death in shaping the organization, differentiation, and overall physiology of these microbial structures.

• MeSH
• biofilmy růst a vývoj   MeSH
• buněčná diferenciace * MeSH
• buněčná smrt MeSH
• kvasinky * cytologie   MeSH
• Saccharomyces cerevisiae * cytologie   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Gcn4p belongs to conserved AP-1 transcription factors involved in many cellular processes, including cell proliferation, stress response, and nutrient availability in yeast and mammals. AP-1 activities are regulated at different levels, such as translational activation or protein degradation, which increases the variability of regulation under different conditions. Gcn4p activity in unstructured yeast liquid cultures increases upon amino acid deficiency and is rapidly eliminated upon amino acid excess. Gcn2p kinase is the major described regulator of Gcn4p that enables GCN4 mRNA translation via the uORFs mechanism. Here, we show that Gcn4p is specifically active in U cells in the upper regions and inactive in L cells in the lower regions of differentiated colonies. Using in situ microscopy in combination with analysis of mutants and strains with GFP at different positions in the translational regulatory region of Gcn4p, we show that cell-specific Gcn4p activity is independent of Gcn2p or other translational or transcriptional regulation. Genetically, biochemically, and microscopically, we identified cell-specific proteasomal degradation as a key mechanism that diversifies Gcn4p function between U and L cells. The identified regulation leading to active Gcn4p in U cells with amino acids and efficient degradation in starved L cells differs from known regulations of Gcn4p in yeast but shows similarities to the activity of AP-1 ATF4 in mammals during insulin signaling. These findings may open new avenues for understanding the parallel activities of Gcn4p/ATF4 and reveal a novel biological role for cell type-specific regulation of proteasome-dependent degradation.IMPORTANCEIn nature, microbes usually live in spatially structured communities and differentiate into precisely localized, functionally specialized cells. The coordinated interplay of cells and their response to environmental changes, such as starvation, followed by metabolic adaptation, is critical for the survival of the entire community. Transcription factor Gcn4p is responsible for yeast adaptation under amino acid starvation in liquid cultures, and its activity is regulated mainly at the level of translation involving Gcn2p kinase. Whether Gcn4p functions in structured communities was unknown. We show that translational regulation of Gcn4p plays no role in the development of colony subpopulations; the main regulation occurs at the level of stabilization of the Gcn4p molecule in the cells of one subpopulation and its proteasomal degradation in the other. This regulation ensures specific spatiotemporal activity of Gcn4p in the colony. Our work highlights differences in regulatory networks in unorganized populations and organized structures of yeast, which in many respects resemble multicellular organisms.

• Klíčová slova
• Saccharomyces cerevisiae, cell-specific regulation, differentiated colonies, proteasomal degradation, spatially structured populations, transcription factor, yeast,
• MeSH
• protein-serin-threoninkinasy metabolismus   genetika   MeSH
• proteolýza MeSH
• proteosyntéza MeSH
• regulace genové exprese u hub * MeSH
• Saccharomyces cerevisiae - proteiny * genetika   metabolismus   MeSH
• Saccharomyces cerevisiae * genetika   metabolismus   MeSH
• stabilita proteinů MeSH
• transkripční faktory bZIP * metabolismus   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• GCN2 protein, S cerevisiae MeSH Prohlížeč
• GCN4 protein, S cerevisiae MeSH Prohlížeč
• protein-serin-threoninkinasy MeSH
• Saccharomyces cerevisiae - proteiny * MeSH
• transkripční faktory bZIP * MeSH

Yeast populations can undergo diversification during their growth and ageing, leading to the formation of different cell-types. Differentiation into two major subpopulations, differing in cell size and density and exhibiting distinct physiological and metabolic properties, was described in planktonic liquid cultures and in populations of colonies growing on semisolid surfaces. Here, we compare stress resistance, metabolism and expression of marker genes in seven differentiated cell subpopulations emerging during cultivation in liquid fermentative or respiratory media and during colony development on the same type of solid media. The results show that the more-dense cell subpopulations are more stress resistant than the less-dense subpopulations under all cultivation conditions tested. On the other hand, respiratory capacity, enzymatic activities and marker gene expression differed more between subpopulations. These characteristics are more influenced by the lifestyle of the population (colony vs. planktonic cultivation) and the medium composition. Only in the population growing in liquid respiratory medium, two subpopulations do not form as in the other conditions tested, but all cells exhibit a range of characteristics of the more-dense subpopulations. This suggests that signals for cell differentiation may be triggered by prior metabolic reprogramming or by an unknown signal from the structured environment in the colony.

• MeSH
• buněčná diferenciace MeSH
• fermentace MeSH
• Saccharomyces cerevisiae * metabolismus   MeSH
• sušené kvasnice * MeSH
• Publikační typ
• časopisecké články MeSH

Single-celled yeasts form spatially structured populations - colonies and biofilms, either alone (single-species biofilms) or in cooperation with other microorganisms (mixed-species biofilms). Within populations, yeast cells develop in a coordinated manner, interact with each other and differentiate into specialized cell subpopulations that can better adapt to changing conditions (e.g. by reprogramming metabolism during nutrient deficiency) or protect the overall population from external influences (e.g. via extracellular matrix). Various omics tools together with specialized techniques for separating differentiated cells and in situ microscopy have revealed important processes and cell interactions in these structures, which are summarized here. Nevertheless, current knowledge is still only a small part of the mosaic of complexity and diversity of the multicellular structures that yeasts form in different environments. Future challenges include the use of integrated multi-omics approaches and a greater emphasis on the analysis of differentiated cell subpopulations with specific functions.

• Klíčová slova
• Biofilms, Cell differentiation, Colonies, Multicellular yeast structures, Regulation, Spatial community structure,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

During development of yeast colonies, various cell subpopulations form, which differ in their properties and specifically localize within the structure. Three branches of mitochondrial retrograde (RTG) signaling play a role in colony development and differentiation, each of them activating the production of specific markers in different cell types. Here, aiming to identify proteins and processes controlled by the RTG pathway, we analyzed proteomes of individual cell subpopulations from colonies of strains, mutated in genes of the RTG pathway. Resulting data, along with microscopic analyses revealed that the RTG pathway predominantly regulates processes in U cells, long-lived cells with unique properties, which are localized in upper colony regions. Rtg proteins therein activate processes leading to amino acid biosynthesis, including transport of metabolic intermediates between compartments, but also repress expression of mitochondrial ribosome components, thus possibly contributing to reduced mitochondrial translation in U cells. The results reveal the RTG pathway's role in activating metabolic processes, important in U cell adaptation to altered nutritional conditions. They also point to the important role of Rtg regulators in repressing mitochondrial activity in U cells.

• Klíčová slova
• Saccharomyces cerevisiae, colony development and differentiation, mitochondrial retrograde signaling, proteomic analysis, yeast colonies,
• MeSH
• aminokyseliny metabolismus   MeSH
• analýza jednotlivých buněk MeSH
• biosyntetické dráhy genetika   MeSH
• chromatografie kapalinová MeSH
• intracelulární signální peptidy a proteiny genetika   metabolismus   MeSH
• mitochondrie genetika   metabolismus   MeSH
• proteom genetika   metabolismus   MeSH
• proteomika MeSH
• regulace genové exprese u hub genetika   MeSH
• represorové proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae genetika   metabolismus   MeSH
• signální transdukce genetika   MeSH
• tandemová hmotnostní spektrometrie MeSH
• transkripční faktory BHLH-Zip genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aminokyseliny MeSH
• intracelulární signální peptidy a proteiny MeSH
• MKS1 protein, S cerevisiae MeSH Prohlížeč
• proteom MeSH
• represorové proteiny MeSH
• RTG1 protein, S cerevisiae MeSH Prohlížeč
• RTG2 protein, S cerevisiae MeSH Prohlížeč
• RTG3 protein, S cerevisiae MeSH Prohlížeč
• Saccharomyces cerevisiae - proteiny MeSH
• transkripční faktory BHLH-Zip MeSH

Yeast form complex highly organized colonies in which cells undergo spatiotemporal phenotypic differentiation in response to local gradients of nutrients, metabolites, and specific signaling molecules. Colony fitness depends on cell interactions, cooperation, and the division of labor between differentiated cell subpopulations. Here, we describe the regulation and dynamics of the expansion of papillae that arise during colony aging, which consist of cells that overcome colony regulatory rules and disrupt the synchronized colony structure. We show that papillae specifically expand within the U cell subpopulation in differentiated colonies. Papillae emerge more frequently in some strains than in others. Genomic analyses further revealed that the Whi2p-Psr1p/Psr2p complex (WPPC) plays a key role in papillae expansion. We show that cells lacking a functional WPPC have a sizable interaction-specific fitness advantage attributable to production of and resistance to a diffusible compound that inhibits growth of other cells. Competitive superiority and high relative fitness of whi2 and psr1psr2 strains are particularly pronounced in dense spatially structured colonies and are independent of TORC1 and Msn2p/Msn4p regulators previously associated with the WPPC function. The WPPC function, described here, might be a regulatory mechanism that balances cell competition and cooperation in dense yeast populations and, thus, contributes to cell synchronization, pattern formation, and the expansion of cells with a competitive fitness advantage.

• Klíčová slova
• chimeric populations, competitive advantage, interaction-specific fitness inequality, interference competition, yeast multicellularity,
• MeSH
• membránové proteiny genetika   metabolismus   MeSH
• proliferace buněk fyziologie   MeSH
• proteinfosfatasy genetika   metabolismus   MeSH
• regulace genové exprese u hub fyziologie   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae genetika   metabolismus   MeSH
• signální transdukce fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• membránové proteiny MeSH
• proteinfosfatasy MeSH
• PSR1 protein, S cerevisiae MeSH Prohlížeč
• PSR2 protein, S cerevisiae MeSH Prohlížeč
• Saccharomyces cerevisiae - proteiny MeSH
• Whi2 protein, S cerevisiae MeSH Prohlížeč

We summarize current knowledge regarding regulatory functions of long noncoding RNAs (lncRNAs) in yeast, with emphasis on lncRNAs identified recently in yeast colonies and biofilms. Potential regulatory functions of these lncRNAs in differentiated cells of domesticated colonies adapted to plentiful conditions versus yeast colony biofilms are discussed. We show that specific cell types differ in their complements of lncRNA, that this complement changes over time in differentiating upper cells, and that these lncRNAs target diverse functional categories of genes in different cell subpopulations and specific colony types.

• MeSH
• biofilmy růst a vývoj   MeSH
• buněčná diferenciace MeSH
• lidé MeSH
• RNA dlouhá nekódující metabolismus   MeSH
• Saccharomyces cerevisiae patogenita   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• RNA dlouhá nekódující MeSH

We present the spatiotemporal metabolic differentiation of yeast cell subpopulations from upper, lower, and margin regions of colonies of different ages, based on comprehensive transcriptomic analysis. Furthermore, the analysis was extended to include smaller cell subpopulations identified previously by microscopy within fully differentiated U and L cells of aged colonies. New data from RNA-seq provides both spatial and temporal information on cell metabolic reprogramming during colony ageing and shows that cells at marginal positions are similar to upper cells, but both these cell types are metabolically distinct from cells localized to lower colony regions. As colonies age, dramatic metabolic reprogramming occurs in cells of upper regions, while changes in margin and lower cells are less prominent. Interestingly, whereas clear expression differences were identified between two L cell subpopulations, U cells (which adopt metabolic profiles, similar to those of tumor cells) form a more homogeneous cell population. The data identified crucial metabolic reprogramming events that arise de novo during colony ageing and are linked to U and L cell colony differentiation and support a role for mitochondria in this differentiation process.

• MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae cytologie   genetika   metabolismus   MeSH
• stanovení celkové genové exprese metody   MeSH
• transkriptom MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• Saccharomyces cerevisiae - proteiny MeSH

Nutrient availability controls the landscape of nutrient transporters present at the plasma membrane, notably by regulating their ubiquitylation and subsequent endocytosis. In yeast, this involves the Nedd4 ubiquitin ligase Rsp5 and arrestin-related trafficking adaptors (ARTs). ARTs are targeted by signaling pathways and warrant that cargo ubiquitylation and endocytosis appropriately respond to nutritional inputs. Here, we show that glucose deprivation regulates the ART protein Csr2/Art8 at multiple levels to trigger high-affinity glucose transporter endocytosis. Csr2 is transcriptionally induced in these conditions through the AMPK orthologue Snf1 and downstream transcriptional repressors. Upon synthesis, Csr2 becomes activated by ubiquitylation. In contrast, glucose replenishment induces CSR2 transcriptional shutdown and switches Csr2 to an inactive, deubiquitylated form. This glucose-induced deubiquitylation of Csr2 correlates with its phospho-dependent association with 14-3-3 proteins and involves protein kinase A. Thus, two glucose signaling pathways converge onto Csr2 to regulate hexose transporter endocytosis by glucose availability. These data illustrate novel mechanisms by which nutrients modulate ART activity and endocytosis.

• MeSH
• arrestin genetika   metabolismus   MeSH
• časové faktory MeSH
• endocytóza * MeSH
• genetická transkripce MeSH
• glukosa nedostatek   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• mutace MeSH
• protein-serin-threoninkinasy metabolismus   MeSH
• proteinfosfatasa 1 metabolismus   MeSH
• proteinkinasy závislé na cyklickém AMP metabolismus   MeSH
• proteiny 14-3-3 metabolismus   MeSH
• proteiny přenášející monosacharidy genetika   metabolismus   MeSH
• regulace genové exprese u hub MeSH
• represorové proteiny metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae genetika   metabolismus   MeSH
• ubikvitinace MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• arrestin MeSH
• BMH1 protein, S cerevisiae MeSH Prohlížeč
• BMH2 protein, S cerevisiae MeSH Prohlížeč
• Csr2 protein, S cerevisiae MeSH Prohlížeč
• glukosa MeSH
• Hxt6 protein, S cerevisiae MeSH Prohlížeč
• HXT7 protein, S cerevisiae MeSH Prohlížeč
• jaderné proteiny MeSH
• MIG1 protein, S cerevisiae MeSH Prohlížeč
• Mig2 protein, S cerevisiae MeSH Prohlížeč
• protein-serin-threoninkinasy MeSH
• proteinfosfatasa 1 MeSH
• proteinkinasy závislé na cyklickém AMP MeSH
• proteiny 14-3-3 MeSH
• proteiny přenášející monosacharidy MeSH
• represorové proteiny MeSH
• Saccharomyces cerevisiae - proteiny MeSH
• SNF1-related protein kinases MeSH Prohlížeč

• Klíčová slova
• aging, cancer, cell differentiation, mitochondria, retrograde signaling, yeast colonies,
• MeSH
• buněčná diferenciace fyziologie   MeSH
• lidé MeSH
• mitochondrie metabolismus   MeSH
• signální transdukce fyziologie   MeSH
• stárnutí buněk fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• úvodníky MeSH