End3p-mediated endocytosis is required for spore wall formation in Saccharomyces cerevisiae.
During sporulation in Saccharomyces cerevisiae, vesicles transported to the vicinity of spindle pole bodies are fused to each other to generate bilayered prospore membranes (PSMs). PSMs encapsulate the haploid nuclei that arise from the meiotic divisions and serve as platforms for spore wall deposition. Membrane trafficking plays an important role in supplying vesicles for these processes. The endocytosis-deficient mutant, end3Delta, sporulated poorly and the spores produced lost resistance to ether vapor, suggesting that END3-mediated endocytosis is important for sporulation. End3p-GFP localized to cell and spore peripheries in vegetative and sporulating cells and colocalized with actin structures. Correspondingly, the actin cytoskeleton appeared aberrant during sporulation in end3Delta. Analysis of meiosis in end3Delta mutants revealed that the meiotic divisions occurred with wild-type kinetics. Furthermore, PSMs were assembled normally. However, the levels of proteins required for spore wall synthesis and components of the spore wall layers at spores were reduced, indicating that end3Delta mutants are defective in spore wall synthesis. Thus, END3-mediated endocytosis is important for spore wall formation. Additionally, cytological analyses suggest that trafficking between the plasma membrane and PSMs is important earlier during sporulation.
Morishita
Masayo
M
Section of Molecular and Cellular Biology, University of California, Davis, California 95616, USA.
Engebrecht
Joanne
J
D000199:Actins / Q000378:metabolism; D002467:Cell Nucleus / Q000502:physiology; D002473:Cell Wall / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D004705:Endocytosis; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006238:Haploidy; D007211:Indoles; D007700:Kinetics; D008540:Meiosis / Q000502:physiology; D009154:Mutation; D010590:Phalloidine / Q000378:metabolism; D011726:Pyridinium Compounds / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D012235:Rhodamines; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D008941:Spindle Apparatus / Q000502:physiology; D013172:Spores, Fungal / Q000737:chemistry / Q000502:physiology*; D014617:Vacuoles / Q000378:metabolism
D000199:Actins; D003598:Cytoskeletal Proteins; C091908:END3 protein, S cerevisiae; C092350:FM 4-64; D005456:Fluorescent Dyes; D007211:Indoles; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D012235:Rhodamines; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; D010590:Phalloidine; C007293:DAPI