Functional roles of a predicted branched chain aminotransferase encoded by the LkBAT1 gene of the yeast Lachancea kluyveri

Montalvo-Arredondo, Javier; Jiménez-Benítez, Ángel; Colón-González, Maritrini; González-Flores, James; Flores-Villegas, Mirelle Citlali; González, Alicia

doi:10.1016/j.fgb.2015.11.004

Cited by 10 publications

(3 citation statements)

References 43 publications

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“…BAT1 and BAT2 arose from the above-mentioned hybridization and whole genome duplication event (WGD), which occurred 100-150 MYA (Kellis et al 2004;Marcet-Houben and Gabaldón 2015). Previous work from our laboratory has shown that the ancestral-type yeasts Kluyveromyces lactis and Lachancea kluyveri, which descend from the pre-WGD ancestor (Kellis et al 2004), each have a single BAT gene, KlBAT1 and LkBAT1, respectively, encoding bifunctional enzymes which are involved in both VIL biosynthesis and catabolism (Colón et al 2011;Montalvo-Arredondo et al 2015). This dual function has been partitioned among the Bat1 and Bat2 paralogous proteins of S. cerevisiae.…”

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Diversification of Transcriptional Regulation Determines Subfunctionalization of Paralogous Branched Chain Aminotransferases in the Yeast Saccharomyces cerevisiae

et al. 2017

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harbors and paralogous genes that encode branched chain aminotransferases and have opposed expression profiles and physiological roles . Accordingly, in primary nitrogen sources such as glutamine, expression is induced, supporting Bat1-dependent valine-isoleucine-leucine (VIL) biosynthesis, while expression is repressed. Conversely, in the presence of VIL as the sole nitrogen source, expression is hindered while that of is activated, resulting in Bat2-dependent VIL catabolism. The presented results confirm that expression is determined by transcriptional activation through the action of the Leu3-α-isopropylmalate (α-IPM) active isoform, and uncovers the existence of a novel α-IPM biosynthetic pathway operating in aΔ mutant grown on VIL, through Bat2-Leu2-Leu1 consecutive action. The classic α-IPM biosynthetic route operates in glutamine through the action of the leucine-sensitive α-IPM synthases. The presented results also show that repression in glutamine can be alleviated in aΔ mutant or through Gcn4-dependent transcriptional activation. Thus, when is grown on glutamine, VIL biosynthesis is predominant and is preferentially achieved through; while on VIL as the sole nitrogen source, catabolism prevails and is mainly afforded by .

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Diversification of Transcriptional Regulation Determines Subfunctionalization of Paralogous Branched Chain Aminotransferases in the Yeast Saccharomyces cerevisiae

et al. 2017

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“…Moreover, YbgE and CaIlvE have the ability to synthesize the l -leucine and l -valine ( Figure 5 ), and they both belong to the branched-chain amino acid family. For the current study on the BCAT, the existing BCATs act on three BCAAs in microorganisms [ 20 , 28 , 33 , 34 , 35 ], but whether the class enzymes can catalyze the synthesis of BCAAs still require further study due to the broad substrate specificities [ 15 ]. However, the YwfG and YhdR did not exhibit activity in the synthesis of l -leucine and l -valine.…”

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confidence: 99%

Improved l-Leucine Production in Corynebacterium glutamicum by Optimizing the Aminotransferases

Feng

Zhang

2018

Molecules

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The production of branched-chain amino acids (BCAAs) is still challenging, therefore we rationally engineered Corynebacterium glutamicum FA-1 to increase the l-leucine production by optimizing the aminotransferases. Based on this, we investigated the effects of the native aminotransferases, i.e., branched-chain amino acid aminotransferase (BCAT; encoded by ilvE) and aspartate aminotransferase (AspB; encoded by aspB) on l-leucine production in C. glutamicum. The strain FA-1△ilvE still exhibited significant growth without leucine addition, while FA-1△ilvE△aspB couldn’t, which indicated that AspB also contributes to L-leucine synthesis in vivo and the yield of leucine reached 20.81 ± 0.02 g/L. It is the first time that AspB has been characterized for l-leucine synthesis activity. Subsequently, the aromatic aminotransferase TyrB and the putative aspartate aminotransferases, the aspC, yhdR, ywfG gene products, were cloned, expressed and characterized for leucine synthesis activity in FA-1△ilvE△aspB. Only TyrB was able to synthesize l-leucine and the l-leucine production was 18.55 ± 0.42 g/L. The two putative branched-chain aminotransferase genes, ybgE and CaIlvE, were also cloned and expressed. Both genes products function efficiently in BCAAs biosynthesis. This is the first report of a rational modification of aminotransferase activity that improves the l-leucine production through optimizing the aminotransferases.

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“…Previous studies of the BCAT genes in pre-WGD yeasts, Kluyveromyces lactis and Lachancea kluyveri reported that two proteoforms with opposing functions are encoded by a single gene BAT1 (Colón et al, 2011; Montalvo-Arredondo et al, 2015). Those studies proposed that the biosynthetic and catabolic roles of the ancestral Bat1 have been partitioned in BAT1 and BAT2 through differential expression and subcellular re-localisation, improving regulation of BCAA metabolism in S. cerevisiae (Montalvo-Arredondo et al, 2015). A number of questions remained unresolved from the previous studies.…”

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confidence: 99%

Regulated use of alternative Transcription Start Sites controls the production of cytosolic or mitochondrial forms of branched-chain aminotransferase in Kluyveromyces marxianus

Coral-Medina

Fenton

Varela

et al. 2022

Preprint

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Following a whole genome duplication (WGD) event approximately 100 million years ago, the yeast lineage from which the model Saccharomyces cerevisiae derives maintained two copies of genes where it was necessary to synthesise proteoforms with different sub-cellular localisation. In contrast, yeasts that did not undergo the WGD event have a single gene that must encode both proteoforms. We adopted an integrated in silico and experimental approach to study how this is achieved with BAT1, a gene that encodes mitochondrial and cytosolic forms of a branched chain aminotransferase (BCAT) in pre-WGD yeast such as Kluyveromyces marxianus. We determined that condition-specific regulation of alternative transcription sites gives rise to mRNA isoforms that differ at the 5’end and that, when decoded, generate a mitochondrial or cytosolic proteoform. Furthermore, targeted mutants lacking specific transcription factors were generated to establish how this differentiation was regulated. As in S. cerevisiae, Gcn4 and Leu3 activated expression of the mRNA encoding the mitochondrial proteoform under conditions when branched chain amino acid synthesis was required. Unlike S. cerevisiae, however, K. marxianus lacked tight regulation of the mRNA encoding the cytosolic proteoform supporting the hypothesis that maintaining paralogous genes in post-WGD yeasts facilitated development of more sophisticated expression control mechanisms.

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Functional roles of a predicted branched chain aminotransferase encoded by the LkBAT1 gene of the yeast Lachancea kluyveri

Cited by 10 publications

References 43 publications

Diversification of Transcriptional Regulation Determines Subfunctionalization of Paralogous Branched Chain Aminotransferases in the Yeast Saccharomyces cerevisiae

Diversification of Transcriptional Regulation Determines Subfunctionalization of Paralogous Branched Chain Aminotransferases in the Yeast Saccharomyces cerevisiae

Improved l-Leucine Production in Corynebacterium glutamicum by Optimizing the Aminotransferases

Regulated use of alternative Transcription Start Sites controls the production of cytosolic or mitochondrial forms of branched-chain aminotransferase in Kluyveromyces marxianus

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