Golgi membranes remain segregated from the endoplasmic reticulum during mitosis in mammalian cells.
What happens to organelles during mitosis, and how they are apportioned to each of the daughter cells, is not completely clear. We have devised a procedure to address whether Golgi membranes fuse with the Endoplasmic Reticulum (ER) during mitosis via the detection of interactions between ER and Golgi proteins. This procedure involves coexpressing an FKBP-tagged Golgi enzyme with an ER-retained protein fused to FRAP in COS cells. Since treatment with rapamycin induces a tight association between FKBP and FRAP, one would expect rapamycin to trap the FKBP-fused Golgi protein in the ER if it ever visits the ER during mitosis. However, after the doubly transfected cells progress through mitosis in the presence of rapamycin, we find the Golgi protein in the newly formed Golgi stacks and not in the ER. Based on these results, we conclude that Golgi membranes remain separate from the ER during mitosis in mammalian cells.
Pecot
Matt Yasuo
MY
Cell and Developmental Biology Department, University of California San Diego, La Jolla, CA 92093, USA.
Malhotra
Vivek
V
D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism; D019556:COS Cells; D004721:Endoplasmic Reticulum / Q000378:metabolism* / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism* / Q000648:ultrastructure; D008322:Mammals; D008938:Mitosis / Q000502:physiology*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012799:Sialyltransferases / Q000378:metabolism; D020123:Sirolimus / Q000494:pharmacology; D022021:Tacrolimus Binding Proteins / Q000378:metabolism
D000944:Antigens, Differentiation, B-Lymphocyte; D000949:Histocompatibility Antigens Class II; D011993:Recombinant Fusion Proteins; C045084:invariant chain; D012799:Sialyltransferases; D017853:Phosphotransferases (Alcohol Group Acceptor); D022021:Tacrolimus Binding Proteins; D020123:Sirolimus