Characterization of two different acyl carrier proteins in complex I from Yarrowia lipolytica

Abstract

Acyl carrier proteins of mitochondria (ACPMs) are small (approximately 10 kDa) acidic proteins that are homologous to the corresponding central components of prokaryotic fatty acid synthase complexes. Genomic deletions of the two genes ACPM1 and ACPM2 in the strictly aerobic yeast Yarrowia lipolytica resulted in strains that were not viable or retained only trace amounts of assembled mitochondrial complex I, respectively. This suggested different functions for the two proteins that despite high similarity could not be complemented by the respective other homolog still expressed in the deletion strains. Remarkably, the same phenotypes were observed if just the conserved serine carrying the phosphopantethein moiety was exchanged with alanine. Although this suggested a functional link to the lipid metabolism of mitochondria, no changes in the lipid composition of the organelles were found. Proteomic analysis revealed that both ACPMs were tightly bound to purified mitochondrial complex I. Western blot analysis revealed that the affinity tagged ACPM1 and ACPM2 proteins were exclusively detectable in mitochondrial membranes but not in the mitochondrial matrix as reported for other organisms. Hence we conclude that the ACPMs can serve all their possible functions in mitochondrial lipid metabolism and complex I assembly and stabilization as subunits bound to complex I.

The LYR protein subunit NB4M/NDUFA6 of mitochondrial complex I anchors an acyl carrier protein and is essential for catalytic activity

“…The presence of a single acyl carrier protein subunit was first discovered in bovine complex I (22). In contrast, Y. lipolytica was shown to harbor two highly similar but mutually nonexchangeable ACPM subunits, ACPM1 and ACPM2 (23). In agreement with our previous study (23), our data show unequivocally that ACPM1 is almost completely associated with complex I in the parental strain (Fig.…”

The mitochondrial acyl carrier protein (ACP) coordinates mitochondrial fatty acid synthesis with iron sulfur cluster biogenesis

“…This is consistent with reports demonstrating that ACP is essential for viability in Yarrowia lipolytica (Dobrynin et al, 2010) and in mammalian cells (Yi and Maeda, 2005; Feng et al, 2009). Moreover, S. cerevisiae mitochondria do not have CI or any structurally similar analog of it.…”

Trypanosoma brucei Mitochondrial Respiratome: Composition and Organization in Procyclic Form

“…7) shows Tb11.02.2070, a long-chain-fatty acid-CoA ligase protein to be associated with subcomplex I␤. In addition, the acyl carrier protein (NDUFAB1) that links subcomplex I␣ with I␤ has homology to two acyl carrier proteins (ACPM1 and ACPM2) of Yarrowia lipolytica, which play roles in mitochondrial fatty acid metabolism as well as complex I assembly (55). Two flavoprotein monooxygenases were also identified as subunits of complex I.…”