A surveillance pathway monitors the fitness of the endoplasmic reticulum to control its inheritance.
The endoplasmic reticulum (ER) plays an essential role in the production of lipids and secretory proteins. Because the ER cannot be generated de novo, it must be faithfully transmitted or divided at each cell division. Little is known of how cells monitor the functionality of the ER during the cell cycle or how this regulates inheritance. We report here that ER stress in S. cerevisiae activates the MAP kinase Slt2 in a new ER stress surveillance (ERSU) pathway, independent of the unfolded protein response. Upon ER stress, ERSU alters the septin complex to delay ER inheritance and cytokinesis. In the absence of Slt2 kinase, the stressed ER is transmitted to the daughter cell, causing the death of both mother and daughter cells. Furthermore, Slt2 is activated via the cell surface receptor Wsc1 by a previously undescribed mechanism. We conclude that the ERSU pathway ensures inheritance of a functional ER.
Babour
Anna
A
Division of Biological Sciences, Section of Molecular Biology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0377, USA.
Bicknell
Alicia A
AA
Tourtellotte
Joel
J
Niwa
Maho
M
D002473:Cell Wall / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological
D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; C119383:SLG1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D020928:Mitogen-Activated Protein Kinases; C072724:SLT2 protein, S cerevisiae