Dictyostelium discoideum requires an Alix/AIP1 homolog, DdAlix, for morphogenesis in alkaline environments.
Alix and its homologs are involved in various phenomena such as endosomal protein-sorting and adaptation to stress conditions. In this study, we found that development of Dictyostelium discoideum Alix (DdAlix) deletion mutant (alx-) cells was impaired in alkaline pH environments. The fruiting body formation efficiency of alx- cells at pH 9.0 was significantly lower than that of wild-type cells (6.8+/-4.2% vs 93+/-6.3%). The alkaline-sensitive phenotype of alx- cells was rescued by addition of salt. The phenotype was rescued by exogenous expression of human Alix as well as DdAlix but not by that of either Saccharomyces cerevisiae Alix homolog Rim20 or Bro1. DdAlix may be, structurally and functionally, more related to human Alix than to yeast Rim20 and Bro1.
Ohkouchi
Susumu
S
Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
Saito
Hajime
H
Aruga
Fumika
F
Maeda
Tatsuya
T
Shibata
Hideki
H
Maki
Masatoshi
M
D000468:Alkalies / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics; D002414:Cations, Monovalent / Q000494:pharmacology; D018797:Cell Cycle Proteins; D004023:Dictyostelium / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D056827:Endosomal Sorting Complexes Required for Transport; D004777:Environment; D017353:Gene Deletion; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008840:Microfilament Proteins / Q000145:classification / Q000235:genetics / Q000502:physiology*; D009024:Morphogenesis; D010802:Phylogeny; D011188:Potassium / Q000494:pharmacology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D012964:Sodium / Q000494:pharmacology; D033921:Vesicular Transport Proteins / Q000235:genetics
D000468:Alkalies; C480237:Bro1 protein, S cerevisiae; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D002414:Cations, Monovalent; D018797:Cell Cycle Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D008840:Microfilament Proteins; C117020:PDCD6IP protein, human; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; C115237:actin interacting protein 1; D012964:Sodium; D011188:Potassium