title: De novo formation of transitional ER sites and Golgi structures in Pichia pastoris.
abstract: Transitional ER (tER) sites are ER subdomains that are functionally, biochemically and morphologically distinct from the surrounding rough ER. Here we have used confocal video microscopy to study the dynamics of tER sites and Golgi structures in the budding yeast Pichia pastoris. The biogenesis of tER sites is tightly linked to the biogenesis of Golgi, and both compartments can apparently form de novo. tER sites often fuse with one another, but they maintain a consistent average size through shrinkage after fusion and growth after de novo formation. Golgi dynamics are similar, although late Golgi elements often move away from tER sites towards regions of polarized growth. Our results can be explained by assuming that tER sites give rise to Golgi cisternae that continually mature.
mesh_terms: D022181:COP-Coated Vesicles / Q000235:genetics / Q000378:metabolism; D002451:Cell Compartmentation / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000648:ultrastructure*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism / Q000648:ultrastructure*; D049452:Green Fluorescent Proteins; D020662:Guanine Nucleotide Exchange Factors; D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure; D008164:Luminescent Proteins; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D018715:Microscopy, Video; D009685:Nuclear Envelope / Q000378:metabolism / Q000648:ultrastructure; D010843:Pichia / Q000166:cytology* / Q000378:metabolism; D011993:Recombinant Fusion Proteins; D013997:Time Factors
chemical_list: D005656:Fungal Proteins; D020662:Guanine Nucleotide Exchange Factors; D008164:Luminescent Proteins; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; C066755:Sec7 guanine nucleotide exchange factors; D049452:Green Fluorescent Proteins