Alternative splicing gives rise to different isoforms of the Neurospora crassa Tob55 protein that vary in their ability to insert beta-barrel proteins into the outer mitochondrial membrane.
Genetics
; 177(1): 137-49, 2007 Sep.
Article
em En
| MEDLINE
| ID: mdl-17660559
ABSTRACT
Tob55 is the major component of the TOB complex, which is found in the outer membrane of mitochondria. A sheltered knockout of the tob55 gene was developed in Neurospora crassa. When grown under conditions that reduce the levels of the Tob55 protein, the strain exhibited a reduced growth rate and mitochondria isolated from these cells were deficient in their ability to import beta-barrel proteins. Surprisingly, Western blots of wild-type mitochondrial proteins revealed two bands for Tob55 that differed by approximately 4 kDa in their apparent molecular masses. Sequence analysis of cDNAs revealed that the tob55 mRNA is alternatively spliced and encodes three isoforms of the protein, which are predicted to contain 521, 516, or 483 amino acid residues. Mass spectrometry of proteins isolated from purified outer membrane vesicles confirmed the existence of each isoform in mitochondria. Strains that expressed each isoform of the protein individually were constructed. When cells expressing only the longest form of the protein were grown at elevated temperature, their growth rate was reduced and mitochondria isolated from these cells were deficient in their ability to assembly beta-barrel proteins.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
RNA Mensageiro
/
Proteínas Fúngicas
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Processamento Alternativo
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Proteínas de Transporte da Membrana Mitocondrial
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Membranas Mitocondriais
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Mitocôndrias
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Neurospora crassa
Idioma:
En
Revista:
Genetics
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Canadá