Akio Kihara

Vps30p/Apg6p is required for both autophagy and sorting of carboxypeptidase Y (CPY). Although Vps30p is known to interact with Apg14p, its precise role remains unclear. We found that two proteins copurify with Vps30p. They were identified by mass spectrometry to be Vps38p and Vps34p, a phosphatidylinositol (PtdIns) 3-kinase. Vps34p, Vps38p, Apg14p, and Vps15p, an activator of Vps34p, were coimmunoprecipitated with Vps30p. These results indicate that Vps30p functions as a subunit of a Vps34 PtdIn

Very long-chain fatty acids (VLCFAs) are fatty acids (FAs) with a chain-length of ≥22 carbons. Mammals have a variety of VLCFAs differing in chain-length and the number of double bonds. Each VLCFA exhibits certain functions, for example in skin barrier formation, liver homeostasis, myelin maintenance, spermatogenesis, retinal function and anti-inflammation. These functions are elicited not by free VLCFAs themselves, but through their influences as components of membrane lipids (sphingolipids and

When secY is overexpressed over secE or secE is underexpressed, a fraction of SecY protein is rapidly degraded in vivo. This proteolysis was unaffected in previously described protease-defective mutants examined. We found, however, that some mutations in ftsH, encoding a membrane protein that belongs to the AAA (ATPase associated with a variety of cellular activities) family, stabilized oversynthesized SecY. This stabilization was due to a loss of FtsH function, and overproduction of the wild-ty

Very long-chain fatty acids are produced through a four-step cycle. However, the 3-hydroxyacyl-CoA dehydratase catalyzing the third step in mammals has remained unidentified. Mammals have four candidates, HACD1-4, based on sequence similarities to the recently identified yeast Phs1, although HACD3 and HACD4 share relatively weak similarity. We demonstrate that all four of these human proteins are indeed 3-hydroxyacyl-CoA dehydratases, in growth suppression experiments using a PHS1-shut off yeast

Glycerophospholipids and sphingolipids are distributed asymmetrically between the two leaflets of the lipid bilayer. Recent studies revealed that certain P-type ATPases and ATP-binding cassette (ABC) transporters are involved in the inward movement (flip) and outward movement (flop) of glycerophospholipids, respectively. In this study of phytosphingosine (PHS)-resistant yeast mutants, we isolated mutants for PDR5, an ABC transporter involved in drug efflux as well as in the flop of phosphatidyle

Sphingoid long-chain bases (LCBs) and long-chain base phosphates (LCBPs) act as signaling molecules in eukaryotic cells. Accumulation of LCBPs results in cell growth inhibition in yeast, although the mechanism is unknown. Here, we identified a novel yeast gene, RSB1 (resistance to sphingoid long-chain base), by screening a multicopy suppressor of the LCB-sensitive phenotype of the LCBP lyase mutant. RSB1 encodes a polypeptide of 354 amino acids with a molecular mass of 40.4 kDa. Rsb1p is predict

The cII gene product of bacteriophage lambda is unstable and required for the establishment of lysogenization. Its intracellular amount is important for the decision between lytic growth and lysogenization. Two genetic loci of Escherichia coli are crucial for these commitments of infecting lambda genome. One of them, hflA encodes the HflKC membrane protein complex, which has been believed to be a protease degrading the cII protein. However, both its absence and overproduction stabilized cII in v

Very long-chain fatty acids (VLCFAs) have a variety of physiological functions and are related to numerous disorders. The key step of VLCFA elongation is catalyzed by members of the elongase family, ELOVLs. Mammals have seven ELOVLs (ELOVL1-7), yet none of them has been purified and analyzed. In the presented study we purified ELOVL7 and measured its activity by reconstituting it into proteoliposomes. Purified ELOVL7 exhibited high activity toward acyl-CoAs with C18 carbon chain length. The calc