Reticulons Regulate the ER Inheritance Block during ER Stress.
Segregation of functional organelles during the cell cycle is crucial to generate healthy daughter cells. In Saccharomyces cerevisiae, ER stress causes an ER inheritance block to ensure cells inherit a functional ER. Here, we report that formation of tubular ER in the mother cell, the first step in ER inheritance, depends on functional symmetry between the cortical ER (cER) and perinuclear ER (pnER). ER stress induces functional asymmetry, blocking tubular ER formation and ER inheritance. Using fluorescence recovery after photobleaching, we show that the ER chaperone Kar2/BiP fused to GFP and an ER membrane reporter, Hmg1-GFP, behave differently in the cER and pnER. The functional asymmetry and tubular ER formation depend on Reticulons/Yop1, which maintain ER structure. LUNAPARK1 deletion in rtn1Δrtn2Δyop1Δ cells restores the pnER/cER functional asymmetry, tubular ER generation, and ER inheritance blocks. Thus, Reticulon/Yop1-dependent changes in ER structure are linked to ER inheritance during the yeast cell cycle.
Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, NSB#1, Room 5328, La Jolla, CA 92093-0377, USA.
Francisco Javier
FJ
Piña
Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, NSB#1, Room 4113, La Jolla, CA 92093-0377, USA.
Tinya
T
Fleming
Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, NSB#1, Room 4113, La Jolla, CA 92093-0377, USA.
Kit
K
Pogliano
Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, NSB#1, Room 5328, La Jolla, CA 92093-0377, USA. Electronic address: niwa@ucsd.edu.
Maho
M
Niwa
D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D059865:Endoplasmic Reticulum Stress; D049452:Green Fluorescent Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism
D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins