Growth of the Mammalian Golgi Apparatus during Interphase.
During the cell cycle, genetic materials and organelles are duplicated to ensure that there is sufficient cellular content for daughter cells. While Golgi growth in interphase has been observed in lower eukaryotes, the elaborate ribbon structure of the mammalian Golgi apparatus has made it challenging to monitor. Here we demonstrate the growth of the mammalian Golgi apparatus in its protein content and volume during interphase. Through ultrastructural analyses, physical growth of the Golgi apparatus was revealed to occur by cisternal elongation of the individual Golgi stacks. By examining the timing and regulation of Golgi growth, we established that Golgi growth starts after passage through the cell growth checkpoint at late G1 phase and continues in a manner highly correlated with cell size growth. Finally, by identifying S6 kinase 1 as a major player in Golgi growth, we revealed the coordination between cell size and Golgi growth via activation of the protein synthesis machinery in early interphase.
Department of Cell and Systems Biology and Biological Sciences, University of Toronto Scarborough, Toronto, Canada.
Alex T-W
AT
Sin
Department of Cell and Systems Biology and Biological Sciences, University of Toronto Scarborough, Toronto, Canada harrison@utsc.utoronto.ca.
Rene E
RE
Harrison
D000818:Animals; D049108:Cell Enlargement; D006056:Golgi Apparatus / Q000378:metabolism / Q000648:ultrastructure*; D006367:HeLa Cells; D006801:Humans; D007399:Interphase; D008322:Mammals / Q000378:metabolism*; D051379:Mice; D046529:Microscopy, Electron, Transmission; D041681:NIH 3T3 Cells; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism*; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000378:metabolism*
D038762:Ribosomal Protein S6 Kinases, 70-kDa; D038744:Ribosomal Protein S6 Kinases, 90-kDa; C512964:Rps6ka1 protein, mouse; C448901:ribosomal protein S6 kinase, 70kD, polypeptide 1