Sphingolipids facilitate age asymmetry of membrane proteins in dividing yeast cells

Pushpendra Singh, Sree Kumar Ramachandran, Jin Zhu, Byoung Choul Kim, Debojyoti Biswas, Taekjip Ha, Pablo A. Iglesias, Rong Li

Research output: Contribution to journalArticlepeer-review

Abstract

One proposed mechanism of cellular aging is the gradual loss of certain cellular components that are insufficiently renewed. In an earlier study, multidrug resistance transporters (MDRs) were postulated to be such aging determinants during the yeast replicative life span (RLS). Aged MDR proteins were asymmetrically retained by the aging mother cell and did not diffuse freely into the bud, whereas newly synthesized MDR proteins were thought to be deposited mostly in the bud before cytokinesis. In this study, we further demonstrate the proposed age asymmetry of MDR proteins in dividing yeast cells and investigate the mechanism that controls diffusive properties of MDR proteins to maintain this asymmetry. We found that long-chain sphingolipids, but not the septin/endoplasmic reticulum-based membrane diffusion barrier, are important for restricting MDR diffusion. Depletion of sphingolipids or shortening of their long acyl chains resulted in an increase in the lateral mobility of MDR proteins, causing aged MDR protein in the mother cell to enter the bud. We used a mathematical model to understand the effect of diminished MDR age asymmetry on yeast cell aging, the result of which was qualitatively consistent with the observed RLS shortening in sphingolipid mutants.

Original languageEnglish (US)
Pages (from-to)2712-2722
Number of pages11
JournalMolecular biology of the cell
Volume28
Issue number20
DOIs
StatePublished - Oct 1 2017

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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