Quantitative proteomics reveals remarkable alterations in the protein abundance response to vanillin
To investigate the changes in protein abundance induced by vanillin stress perturbation, the proteomic differences were examined in the BY4741 laboratory strain in samples treated with and without vanillin. Based upon our stringent data mining criteria, a threshold of 1.3-fold was applied to filter out proteins that are differentially expressed. Among them, 135 proteins were up-regulated, and 83 proteins were down-regulated in response to vanillin (P-value < 0.05). Functional annotation of all the identified proteins was conducted based on the Gene Ontology (GO) database [12] and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database [13]. The KEGG pathway enrichment of the different expressed proteins (DEPs) suggests that activated protein genes are mainly involved in the functional categories of energy production, amino acid metabolism and transport, the biosynthesis of secondary metabolites and others (Fig. 1a). In contrast, repressed protein genes are largely involved in the functional categories of ribosome, amino acid metabolism and biosynthesis of secondary metabolites (Fig. 1b).
Proteomes exhibited visible differences from transcriptomes in the presence of vanillin
Considering of the repression of the translation initiated by vanillin, mRNA most likely cannot represent a protein situation. Thus, the proteomic dataset was compared to data from a previous transcriptomic outcome (GEO accession number: GSE89854) to investigate the correlation between mRNA and protein levels [6]. Overlaps (i.e., homo-directional) between DEPs and differentially expressed genes (DEGs) are shown in the Venn diagrams (Fig. 2a). Only 23.8% of these DEPs exhibited a homo-directional change at the level of their transcript counterparts. A scatter plot was used to compare high-quality protein with the transcript expression ratios for all 218 DEPs (Fig. 2b). The positive Spearman rank correlation coefficient (Sr) of 0.47 that was calculated for these 218 DEPs revealed a weak correlation between transcriptome and proteome. This phenomenon is likely due to vanillin’s ability to repress translation [7].
The DEPs and DEGs enriched (p < 0.05) in KEGG pathways are listed in Fig. 2c. Glycolysis-related genes/proteins and ABC transporters were up-regulated both at the mRNA and protein levels, which indicates that vanillin stimulates these two categories at the transcriptional level. Both the “pentose phosphate pathway (PPP)” and the “ribosome biogenesis pathway” were down-regulated only at the mRNA level. Ribosomal proteins and RNA polymerases were significantly decreased only at the protein level, which indicates that vanillin might repress the translation of the corresponding proteins or influence their post-transcriptional regulation.
Ribosomal proteins and rRNA processing-related proteins significantly decreased under vanillin stress
Although the transcriptome showed that 13 genes related to ribosome biogenesis were notably down-regulated (Table 1), the corresponding proteins exhibited no changes in protein abundance [6]. However, 20 ribosomal proteins were sharply suppressed by vanillin, including 5 small subunits of ribosomes (40S) and 15 large ribosomal subunits (60S) (Table 1). Moreover, one ribosome biogenesis-related protein (Rlp24) [14], three proteins (Esf1, Nsa2, Pop8) involved in rRNA processing, two RNA polymerase I subunits (Rpa12, Rpa190), one RNA polymerase III subunit (Rpc11), tRNA 4-demethylwyosine synthase Tyw1, and ATPase for tRNA processing Nbp35 also displayed a visible decrease in protein abundance. These down-regulated proteins were constituents of the cellular translational machine, which indicates that vanillin blocks translation efficiency and protein synthesis by reducing the quantity of ribosomal proteins available. This phenomenon coincided with the facts that vanillin inhibits translation initiation, so the cells do not need many more ribosomes. Therefore, the reduction of ribosome biogenesis is likely representative of the cell’s effort to conserve energy for survival since ribosome biogenesis demands a great supply of energy [15, 16].
Table 1
Differentially expressed genes/proteins related to ribosomal proteins, ribosome biogenesis and rRNA processing in response to vanillin stress
ORF | Protein/gene | Description | DEPs Ratioa /DEGs log2 ratiob |
Ribosomal proteins at protein level | DEPs Ratio |
YDR025W | Rps11a | ribosomal 40S subunit protein S11A | 0.724 |
YPR132W | Rps23b | ribosomal 40S subunit protein S23B | 0.753 |
YLR388W | Rps29a | ribosomal 40S subunit protein S29A | 0.660 |
YDL061C | Rps29b | ribosomal 40S subunit protein S29B | 0.610 |
YNL096C | Rps7b | ribosomal 40S subunit protein S7B | 0.763 |
YKL006W | Rpl14a | ribosomal 60S subunit protein L14A | 0.695 |
YHL001W | Rpl14b | ribosomal 60S subunit protein L14B | 0.709 |
YGR148C | Rpl24b | ribosomal 60S subunit protein L24B | 0.727 |
YBL092W | Rpl32 | ribosomal 60S subunit protein L32 | 0.755 |
YPL143W | Rpl33a | ribosomal 60S subunit protein L33A | 0.656 |
YOR234C | Rpl33b | ribosomal 60S subunit protein L33B | 0.644 |
YIL052C | Rpl34b | ribosomal 60S subunit protein L34B | 0.707 |
YMR194W | Rpl36a | ribosomal 60S subunit protein L36A | 0.752 |
YPL249C-A | Rpl36b | ribosomal 60S subunit protein L36B | 0.743 |
YLR185W | Rpl37a | ribosomal 60S subunit protein L37A | 0.740 |
YLR325C | Rpl38 | ribosomal 60S subunit protein L38 | 0.719 |
YNL162W | Rpl42a | ribosomal 60S subunit protein L42A | 0.765 |
YPR043W | Rpl43a | ribosomal 60S subunit protein L43A | 0.700 |
YPL198W | Rpl7b | ribosomal 60S subunit protein L7B | 0.683 |
YHL033C | Rpl8a | ribosomal 60S subunit protein L8A | 0.746 |
rRNA processing at protein level |
YDR365C | Esf1 | Nucleolar protein involved in pre-rRNA processing | 0.742 |
YBL018C | Pop8 | ribonuclease P | 0.750 |
YER126C | Nsa2 | rRNA-processing protein NSA2 | 0.727 |
YDR279W | Rnh202 | Ribonuclease H2 subunit | 0.710 |
YJR063W | Rpa12 | RNA polymerase I core subunit RPA12 | 0.750 |
YOR341W | Rpa190 | RNA polymerase I core subunit RPA190 | 0.746 |
YDR045C | Rpc11 | RNA polymerase III core subunit RPC11 | 0.730 |
YLR009W | Rlp24 | ribosome biosynthesis protein | 0.719 |
Ribosome biogenesis at mRNA level | DEGs log2 ratio |
YOL077C | Brx1 | ribosome biogenesis protein | -1.4 |
YAL025C | Mak16 | ribosome biosynthesis protein | -1.2 |
YOL041C | Nop12 | involved in biogenesis of large 60S ribosomal subunit | -1.3 |
YPL043W | Nop4 | mRNA-binding ribosome biosynthesis protein | -1.0 |
YDR496C | Puf6 | negative regulation of translation, ribosomal large subunit biogenesis | -1.5 |
YHR066W | Ssf1 | rRNA-binding ribosome biosynthesis protein | -1.1 |
YPL226W | New1 | ATP binding cassette protein | -1.1 |
YGR159C | Nsr1 | required for pre-rRNA processing and ribosome biogenesis | -1.4 |
YDR398W | Utp5 | Subunit of U3-containing Small Subunit processome complex | -1.0 |
YDR299W | Bfr2 | rRNA-processing protein | -1.3 |
YNL112W | Dbp2 | DEAD-box ATP-dependent RNA helicase | -1.5 |
YAL025C | Mak16 | ribosome biosynthesis protein | -1.2 |
YOL041C | Nop12 | Nucleolar protein involved in pre-25S rRNA processing | -1.3 |
a DEPs ratio (BY4741with/without vanillin stress) which is less than 1 means down-regulation at protein level. |
b log2 ratio (BY4741with/without vanillin stress) which is less than 0 means down-regulation at mRNA level. |
Vanillin stress increased the quantity of proteins involved in energy generation
As shown in Table 2, a number of enzymes involved in energy generation pathways, such as glycolysis, oxidative phosphorylation, and the PPP, were dramatically up-regulated. Six glycolytic enzymes (Pyc1p, Tdh1, Tdh2, Hxk2, Eno1, and Gpm2) associated with glycolysis were remarkably increased. In particular, Hxk2, the predominant enzyme that catalyzes the first irreversible step of glycolysis [17], was up-regulated more than 1.5 times. Hxk2 is first of two rate-limiting enzymes in glycolysis [18]. Moreover, the proteins related to adenosine triphosphatase (ATP) synthesis, including the five ATP synthase subunits (Atp20, Atp7, Atp15, Atp14, and Tim11), three cytochrome c oxidase subunits (Cox4, Cox12, and Cox8), four ubiquinol cytochrome-c reductase subunits (Qcr9, Qcr2, Cor1, and Qcr6), and one ATPase (Pma2), also increased significantly. The up-regulated glycolysis and oxidative phosphorylation pathways tend to supply more ATP for cellular survival as the detoxification of vanillin consumes energy. For example, when facing vanillin stress, one strategy is to up-regulate some ATP binding cassette (ABC) transporters, such as Pdr5 and Snq2 (up-regulated 1.68 and 3.78 times, respectively, at the protein level), to extrude vanillin from the cells. These two transporters were also up-regulated at the mRNA level [6].
Table 2
Differentially expressed proteins related to energy metabolism in response to vanillin
ORF | Protein name | Description | DEPs Ratioa |
ATP biosynthetic process |
YPR020W | Atp20 | F1F0 ATP synthase subunit g | 1.37 |
YKL016C | Atp7 | F1F0 ATP synthase subunit d | 1.33 |
YPL271W | Atp15 | F1F0 ATP synthase subunit epsilon | 1.43 |
YLR295C | Atp14 | F1F0 ATP synthase subunit h | 2.04 |
YPL036W | Pma2 | H (+)-exporting P2-type ATPase | 1.39 |
YDR322C-A | Tim11 | F1F0 ATP synthase subunit e | 1.35 |
electron transport and membrane-associated energy conservation |
YGR183C | Qcr9 | ubiquinol-cytochrome-c reductase subunit 9 | 1.43 |
YPR191W | Qcr2 | ubiquinol-cytochrome-reductase | 1.33 |
YBL045C | Cor1 | ubiquinol-cytochrome-reductase | 1.34 |
YGL187C | Cox4 | cytochrome c oxidase subunit IV | 1.37 |
YLR038C | Cox12 | cytochrome c oxidase subunit VIb | 1.32 |
YFR033C | Qcr6 | ubiquinol-cytochrome-c reductase subunit 6 | 1.31 |
YLR395C | Cox8 | cytochrome c oxidase subunit VIII | 1.38 |
Glycolysis/gluconeogenesis | |
YGR254W | Eno1 | phosphopyruvate hydratase ENO1 | 1.52 |
YJL052W | Tdh1 | Glyceraldehyde-3-phosphate dehydrogenase | 1.84 |
YGL253W | Hxk2 | hexokinase 2 | 1.53 |
YDL021W | Gpm2 | phosphoglycerate mutase family | 1.41 |
YJR009C | Tdh2 | Glyceraldehyde-3-phosphate dehydrogenase | 1.69 |
YGL062W | Pyc1 | pyruvate carboxylase 1 | 1.31 |
pentose-phosphate shunt, oxidative branch |
YHR183W | Gnd1 | phosphogluconate dehydrogenase | 1.64 |
YHR163W | Sol3 | 6-phosphogluconolactonase | 1.51 |
a DEPs ratio (BY4741with/without vanillin stress) which is less than 1 means down-regulation. |
Two enzymes (Gnd1 and Sol3) of the PPP increased over 1.5 times, especially the enzyme Gnd1, which generates nicotinamide adenine dinucleotide phosphate (NADPH) during its catalysis [19]. The PPP is the major source of NADPH, a vital cofactor for vanillin conversion to vanillyl alcohol, which is less toxic than vanillin [20, 21]. In the face of vanillin stress, another resistance strategy of S. cerevisiae is utilization of NADPH-dependent alcohol dehydrogenase (ADH) enzymes, such as Adh6/7, for vanillin transformation [22, 23]. |
Thus, the lower number of ribosomal proteins and ribosome biogenesis proteins to conserve energy as well as the higher level of glycolysis and oxidative phosphorylation pathway for producing more energy are thought to be an adaption of yeast for survival in response to vanillin stress.
Comparative proteomics analysis of the deletion of YRR1
Our previous study found that vanillin repressed ribosome biogenesis and pathways. In addition, the deletion of YRR1 could lower this repression and lead to improving resistance of S. cerevisiae to vanillin [6]. Thus, YRR1 was considered to be related to ribosome biogenesis or translation pathways. However, the known YRR1 targets are mostly related to ABC transporters and permeases, not the two aforementioned pathways. Further, the deletion of YRR1 triggered only eight genes (YBR230W-A, CAR2, FMP45, YCL048W-A, SCS3, UTH1, PMP3, and YIL002W-A), which have no effect on vanillin resistance expressed differently at the mRNA level (data not shown). To investigate the protein quantity changes caused by deleting YRR1, a proteomic analysis was conducted between BY4741(yrr1Δ) and BY4741. The outcome revealed that there were 121 DEPs, including 112 up-regulated and 9 down-regulated proteins that had no overlap with their corresponding mRNA level. The up-regulated DEPs were divided into functional categories according to the MIPS Functional Catalog and mainly felt in transcription, translation, and energy generation categories (Table 3). The functions of differentially expressed proteins are listed in Table 4.
Table 3
Functional classification of up-regulated proteins of YRR1 deletion
MIPS functional category | Number of genes in category | P-value |
RNA transport | 9 | 1 × 10− 5 |
transcriptional control | 19 | 5 × 10− 5 |
energy generation | 4 | 3 × 10− 4 |
electron transport | 7 | 4 × 10− 4 |
rRNA processing | 9 | 1 × 10− 3 |
RNA binding | 9 | 3 × 10− 3 |
translation elongation | 3 | 4 × 10− 3 |
translation termination | 2 | 0.01 |
Significance was estimated with FunSpec (http://funspec.med.utoronto.ca/) based on the hypergeometric distribution of the MIPS functional categories of the differentially expressed proteins compared to the yeast proteome (P-value smaller than 0.01, bonferroni correction applied). |
The deletion of YRR1 stimulated quantity changes of translational proteins |
In the present proteomic data, a series of rRNA processing proteins were up-regulated after deleting YRR1. Among them, Nop6, Nhp2, Naf1, Lsm5, Nsr1, and Fyv7 participate in the synthesis of the 40S (small) ribosomal subunit. Cgr1 is involved in processing rRNA for the 60S ribosomal subunit [24]. The elements of rRNA synthesis also displayed increases, including the subunit of RNA polymerase I Rpa34, the RNA polymerase III assembly protein Rbs1, and two transcription factors (Hmo1 and Abf1) involved in activating rRNA and ribosomal protein transcription under the control of the TOR pathway [25–27]. Moreover, several regulators of translation, including three translation initiation factors (Tif11, Hcr1, and Gis2), were also up-regulated. Considering its ability to repress ribosome genesis and translation by vanillin stress, the deletion of YRR1 might strengthen translational elements to promote vanillin resistance in yeast. |
Intriguingly, three translational suppressors also increased, including two 4E-binding proteins, Caf20 and Eap1, which inhibit translational initiation by competing with translation initiation factor eIF4G to bind with eIF4E [28]. The other translational repressor was Stm1, which was previously demonstrated to repress translational elongation by limiting the interaction of elongation factor eEF3 with ribosomes and stalling ribosomes [29]. Further, one recent study indicated that Stm1 also worked as a ribosome preservation factor in response to nutrient stress and facilitated ribosomal protein synthesis rates once nutrients are restored [30]. These three proteins assist with the formation of P-bodies [31, 32]. P-bodies are viewed as reservoirs of mRNA after translation inhibition, and they are later released to reenter translation [33, 34]. It is likely that the absence of YRR1 can protect yeast cells against vanillin stress by promoting the formation of P-bodies to store translation elements and saving energy for the de-novo synthesis of translation machinery. |
The deletion of YRR1 promotes RNA polymerase II-directed transcription |
Table 4
Differentially expressed proteins induced by the deletion of YRR1
ORF | Protein | Description | DEPs ratioa |
regulation of translation |
YOR276W | Caf20 | Phosphoprotein of the mRNA cap-binding complex | 1.64 |
YKL204W | Eap1 | eIF4E-associated protein | 1.39 |
YNL255C | Gis2 | mRNA-binding translational activator | 1.40 |
YCL037C | Sro9 | RNA-binding protein | 1.31 |
YHR087W | Rtc3 | Protein of unknown function involved in RNA metabolism | 1.43 |
YDR432W | Npl3 | mRNA-binding protein promotes elongation, regulates termination | 1.37 |
YDL053C | Pbp4 | Pbp1p binding protein | 1.39 |
YOL123W | HRP1 | required for the cleavage and polyadenylation of pre-mRNA 3' ends | 1.31 |
YLR150W | Stm1 | Protein required for optimal translation under nutrient stress | 1.42 |
rRNA processing | |
YER146W | Lsm5 | possibly involved in processing tRNA, snoRNA, and rRNA | 1.31 |
YDL208W | Nhp2 | snoRNA-binding protein NHP2 rRNA processing | 1.42 |
YGL029W | Cgr1 | Protein involved in processing of pre-rRNA | 1.60 |
YGR159C | Nsr1 | pre-rRNA processing and ribosome biogenesis | 1.40 |
YLR192C | Hcr1 | translation initiation factor eIF3 core subunit | 1.43 |
YNL124W | Naf1 | RNA-binding snoRNA assembly | 1.67 |
YLR068W | Fyv7 | Nucleolar protein required for maturation of 18S rRNA | 1.36 |
transcription by RNA polymerase I |
YDR174W | Hmo1 | Chromatin associated high mobility group | 1.38 |
YMR263W | Sap30 | Component of Rpd3L histone deacetylase complex | 1.39 |
YER088C | Dot6 | Protein involved in rRNA and ribosome biogenesis | 1.37 |
YJL148W | Rpa34 | RNA polymerase I subunit A34.5 | 1.47 |
YDL213C | Nop6 | rRNA-binding protein required for 40S ribosomal subunit biogenesis | 1.44 |
YMR260C | Tif11 | Translation initiation factor eIF1A | 1.36 |
nucleobase-containing compound transport |
YOR098C | Nup1 | FG-nucleoporin NUP1 | 1.35 |
YLR335W | Nup2 | FG-nucleoporin NUP2 | 1.43 |
YGR119C | Nup57 | FG-nucleoporin NUP57 | 1.33 |
YJL041W | NSP1 | FG-nucleoporin NSP1 | 1.55 |
microRNA biogenesis |
YDL189W | Rbs1 | assembly of the RNA polymerase III complex | 1.40 |
Transcription factor and cofactor |
YDR167W | Taf10 | Subunit of TFIID and SAGA complexes | 1.53 |
YLR399C | Bdf1 | Protein involved in transcription initiation associates with the basal transcription factor TFIID | 1.46 |
YKL112W | Abf1 | DNA-binding protein ABF1 | 1.36 |
YPR133C | Spn1 | Protein involved in RNA polymerase II transcription | 1.35 |
YJR060W | Cbf1 | Basic helix-loop-helix (bHLH) protein | 1.57 |
YOR298C-A | Mbf1 | Transcriptional coactivator transcription by RNA polymerase II | 1.47 |
YER159C | Bur6 | negative cofactor 2 transcription regulator complex subunit BUR6 | 1.38 |
YBR089C-A | Nhp6B | high-mobility group nucleosome-binding protein | 1.47 |
YGL025C | Pgd1 | Subunit of the RNA polymerase II mediator complex essential for basal and activated transcription | 1.38 |
Transcription process regulation |
YML094W | Gim5 | facilitates transcriptional elongation | 1.43 |
YLR200W | Yke2 | facilitates transcriptional elongation | 1.53 |
Stress response | |
YLR150W | Stm1 | Protein required for optimal translation under nutrient stress | 1.42 |
YML007W | Yap1 | DNA-binding transcription factor YAP1 | 1.60 |
YPR008W | Haa1 | Transcriptional activator involved in adaptation to weak acid stress | 1.57 |
YNL027W | Crz1 | Transcription factor, activates transcription of stress response genes | 1.75 |
YMR074C | Sod2 | superoxide dismutase | 1.32 |
YJR104C | Sod1 | superoxide dismutase | 1.39 |
YDL110C | Tma17 | ATPase dedicated chaperone that adapts proteasome assembly to stress; | 1.59 |
YBL051C | Pin4 | Protein involved in G2/M phase progression and response to DNA damage | 1.49 |
YKL054C | Def1 | DNA damage-responsive RNA polymerase-degradation factor DEF1 | 1.65 |
YFL014W | Hsp12 | lipid-binding protein HSP12, induced by heat shock, oxidative stress | 1.64 |
a DEPs ratio (BY4741(yrr1Δ)/ BY4741) which is more than 1 means up-regulation. |
Arbitrary extracellular and intracellular stimulation can trigger a global adaptive transcriptional regulatory program in yeast cells. The deletion of YRR1 up-regulated several basal transcription factors (Taf10, Mbf1, Nhp6b, and Pgd1). These factors assist in recognizing promoters that contain a TATA box and assembly of the transcription preinitiation complex and thereby promote transcription of TATA-containing genes [35–38]. TATA-containing genes tend to be stress-responsive [39, 40]. Moreover, four transcription elongation factors (Gim5, Yke2, Spn1, and Npl3) also increased in conditions of protein abundance. Npl3, an mRNA-binding protein, is a positive transcription elongation factor shown to interact with the carboxy terminal domain (CTD) and have a direct stimulatory effect on the elongation activity of the polymerase [41]. Therefore, these results indicate that the deletion of YRR1 promotes TATA-containing gene transcription by the promotion of basal transcription factors to improve survival under vanillin stress.
The deletion of YRR1 improved S. cerevisiae’s resistance to vanillin by increasing Tma17, Mbf1, and Haa1 at the protein level
The results of above proteomic analysis led us to investigate possible novel mechanisms between the deletion of YRR1 and a vanillin-tolerant phenotype. First, two proteins attracted our attention since they exhibited reverse variation in two proteomes: Rtc3, which is involved in RNA metabolism, and plasma membrane protein Hsp12, which plays a role in maintaining membrane organization. They were both down-regulated by vanillin stress but up-regulated by YRR1 deletion. Their reverse variation is likely the reason why YRR1 deletion promotes the resistance of yeast to vanillin stress. However, the overexpression of these proteins had no effect on vanillin resistance (data not shown).
We investigated several up-regulated proteins that were associated with transcription and the stress response in a YRR1-deletion strain as candidates. These candidates were six stress response-related proteins (Crz1, Dsk2, Hsp12, Haa1, Def1, and Tma17) and four transcription-related proteins (Taf10, Mbf1, Gis2, and Tif11). To test these proteins’/genes’ function in a vanillin-resistant phenotype, these genes were overexpressed in BY4741. The overexpression of HAA1, TMA17, and MBF1 enhanced the strain growth under vanillin stress (Fig. 3 and Fig. 4). The maximum specific growth rates of the transformants of HAA1, TMA17, and MBF1 were 18%, 33%, and 15% faster than the control in the presence of 6 mM vanillin, respectively (Table 5). The specific consumption rates for vanillin of strains overexpressing HAA1, TMA17, and MBF1 were 0.041, 0.041, and 0.029 g g− 1 h− 1, respectively. Compared to the 0.034 g g− 1 h− 1 of the control (Table 5), only HAA1 and TMA17 significantly increased the specific vanillin consumption rates. MBF1 accelerated growth more than vanillin reduction. However, other genes related to translation did not significantly improve vanillin resistance (data not shown).
Table 5
Maximum specific growth rate and specific consumption rate for vanillin of recombinant strains
Strains | SD medium | SD with 6 mM vanillin |
| µmax (h− 1) | µmax (h− 1) | specific consumption rate for vanillin (g g− 1 h− 1) |
BY4741(pJFE3) | 0.273 ± 0.008 | 0.087 ± 0.005 | 0.034 ± 0.003 |
BY4741(HAA1) | 0.252 ± 0.007 | 0.109 ± 0.002 | 0.041 ± 0.003 |
BY4741(TMA17) | 0.280 ± 0.008 | 0.117 ± 0.002 | 0.041 ± 0.004 |
BY4741(MBF1) | 0.116 ± 0.007 | 0.097 ± 0.005 | 0.029 ± 0.004 |
Haa1 is a critical transcription factor involved in the acid stress adaption of yeast cells [42]. It also contributes to vanillin resistance, which indicates that vanillin and acid stress share some common features, such as stimulating reactive oxygen species accumulation and inhibiting translation [7, 9, 43, 44]. Mbf1 is a transcriptional coactivator that mediates transcriptional activation by bridging the DNA-binding region of the activator and TBP (TATA binding protein) [45]. As mentioned above, TATA-containing genes are mainly associated with stress responses. Therefore, it was expected that Mbf1 could improve S. cerevisiae vanillin resistance by facilitating stress-response gene transcription. Under stress conditions, Tma17 (also named as Adc17) is the most important chaperone for yeast cellular proteasome biogenesis and assembly. The deletion of TMA17 aggravates proteasome defects and reduced the cells’ fitness. The maintenance of adequately functional proteasomes is vital for cells and organisms to adapt to changes and survive in their environment [46]. Thus, the deletion of YRR1 stimulated greater Tma17 expression to allow cells to adapt to vanillin stress better. These results suggested that the deletion of YRR1 could up-regulate HAA1, TMA17, and MBF1 at the protein level to enhance vanillin resistance.