Genetic Evaluation of Peroxisomal and Cytosolic Acetoacetyl-CoA Thiolase Isozymes in n-Alkane-Assimilating Diploid Yeast, Candida tropicalis

Mitsuyoshi Ueda, Naoki Kanayama, Atsuo Tanaka

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The n-alkane-assimilating diploid yeast, Candida tropicalis, possesses two acetoacetyl-CoA thiolase (Thiolase I) isozymes encoded by one allele: peroxisomal and cytosolic Thiolase Is encoded by both CT-T1A and CT-T1B. To clarify the function of peroxisomal and cytosolic Thiolase Is, the site-directed mutation leading Thiolase I ΔC6 without a putative C-terminal peroxisomal targeting signal was introduced on CT-T1A locus in the ct-t1bΔ-null mutant. The C-terminus-truncated Thiolase I was active and solely present in the cytosol. Although the ct-t1aΔ/t1bΔ-null mutants showed mevalonate auxotrophy, the mutants having the C-terminus-truncated Thiolase I did not require mevalonate for growth, as did the strains having cytosolic Thiolase I. These results demonstrate that the presence of Thiolase I in the cytoplasm is indispensable for the sterol synthesis in this yeast. It is of greater interest that peroxisomal and cytosolic Thiolase I isozymes, products of the same genes, play different roles in the respective compartments, although further investigations will be necessary to analyze how to be sorted into peroxisomes and the cytosol.

Original languageEnglish
Pages (from-to)285-290
Number of pages6
JournalCell Biochemistry and Biophysics
Volume32
Publication statusPublished - 2000
Externally publishedYes

Fingerprint

Acetyl-CoA C-Acetyltransferase
Candida tropicalis
Mevalonic Acid
Alkanes
Candida
Diploidy
Cytosol
Yeast
Isoenzymes
Yeasts
Peroxisomes
Sterols
Cytoplasm
Genes
Alleles
Mutation
Growth

Keywords

  • 3-ketoacyl-CoA thiolase
  • Acetoacetyl-CoA thiolase
  • Candida tropicalis
  • Cytosol
  • Mevalonate
  • Peroxisome

ASJC Scopus subject areas

  • Biophysics
  • Cell Biology
  • Clinical Biochemistry

Cite this

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title = "Genetic Evaluation of Peroxisomal and Cytosolic Acetoacetyl-CoA Thiolase Isozymes in n-Alkane-Assimilating Diploid Yeast, Candida tropicalis",
abstract = "The n-alkane-assimilating diploid yeast, Candida tropicalis, possesses two acetoacetyl-CoA thiolase (Thiolase I) isozymes encoded by one allele: peroxisomal and cytosolic Thiolase Is encoded by both CT-T1A and CT-T1B. To clarify the function of peroxisomal and cytosolic Thiolase Is, the site-directed mutation leading Thiolase I ΔC6 without a putative C-terminal peroxisomal targeting signal was introduced on CT-T1A locus in the ct-t1bΔ-null mutant. The C-terminus-truncated Thiolase I was active and solely present in the cytosol. Although the ct-t1aΔ/t1bΔ-null mutants showed mevalonate auxotrophy, the mutants having the C-terminus-truncated Thiolase I did not require mevalonate for growth, as did the strains having cytosolic Thiolase I. These results demonstrate that the presence of Thiolase I in the cytoplasm is indispensable for the sterol synthesis in this yeast. It is of greater interest that peroxisomal and cytosolic Thiolase I isozymes, products of the same genes, play different roles in the respective compartments, although further investigations will be necessary to analyze how to be sorted into peroxisomes and the cytosol.",
keywords = "3-ketoacyl-CoA thiolase, Acetoacetyl-CoA thiolase, Candida tropicalis, Cytosol, Mevalonate, Peroxisome",
author = "Mitsuyoshi Ueda and Naoki Kanayama and Atsuo Tanaka",
year = "2000",
language = "English",
volume = "32",
pages = "285--290",
journal = "Cell Biochemistry and Biophysics",
issn = "1085-9195",
publisher = "Humana Press",

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TY - JOUR

T1 - Genetic Evaluation of Peroxisomal and Cytosolic Acetoacetyl-CoA Thiolase Isozymes in n-Alkane-Assimilating Diploid Yeast, Candida tropicalis

AU - Ueda, Mitsuyoshi

AU - Kanayama, Naoki

AU - Tanaka, Atsuo

PY - 2000

Y1 - 2000

N2 - The n-alkane-assimilating diploid yeast, Candida tropicalis, possesses two acetoacetyl-CoA thiolase (Thiolase I) isozymes encoded by one allele: peroxisomal and cytosolic Thiolase Is encoded by both CT-T1A and CT-T1B. To clarify the function of peroxisomal and cytosolic Thiolase Is, the site-directed mutation leading Thiolase I ΔC6 without a putative C-terminal peroxisomal targeting signal was introduced on CT-T1A locus in the ct-t1bΔ-null mutant. The C-terminus-truncated Thiolase I was active and solely present in the cytosol. Although the ct-t1aΔ/t1bΔ-null mutants showed mevalonate auxotrophy, the mutants having the C-terminus-truncated Thiolase I did not require mevalonate for growth, as did the strains having cytosolic Thiolase I. These results demonstrate that the presence of Thiolase I in the cytoplasm is indispensable for the sterol synthesis in this yeast. It is of greater interest that peroxisomal and cytosolic Thiolase I isozymes, products of the same genes, play different roles in the respective compartments, although further investigations will be necessary to analyze how to be sorted into peroxisomes and the cytosol.

AB - The n-alkane-assimilating diploid yeast, Candida tropicalis, possesses two acetoacetyl-CoA thiolase (Thiolase I) isozymes encoded by one allele: peroxisomal and cytosolic Thiolase Is encoded by both CT-T1A and CT-T1B. To clarify the function of peroxisomal and cytosolic Thiolase Is, the site-directed mutation leading Thiolase I ΔC6 without a putative C-terminal peroxisomal targeting signal was introduced on CT-T1A locus in the ct-t1bΔ-null mutant. The C-terminus-truncated Thiolase I was active and solely present in the cytosol. Although the ct-t1aΔ/t1bΔ-null mutants showed mevalonate auxotrophy, the mutants having the C-terminus-truncated Thiolase I did not require mevalonate for growth, as did the strains having cytosolic Thiolase I. These results demonstrate that the presence of Thiolase I in the cytoplasm is indispensable for the sterol synthesis in this yeast. It is of greater interest that peroxisomal and cytosolic Thiolase I isozymes, products of the same genes, play different roles in the respective compartments, although further investigations will be necessary to analyze how to be sorted into peroxisomes and the cytosol.

KW - 3-ketoacyl-CoA thiolase

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KW - Cytosol

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KW - Peroxisome

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