The sensitivity of saccharomyces mutants to palmitoleic acid may provide a means to study the controls of membrane fluidity in eukaryotes

Lockshon, Daniel and Kerr, Emily O. and Learmonth, Robert P. and Kennedy, Brian K. (2007) The sensitivity of saccharomyces mutants to palmitoleic acid may provide a means to study the controls of membrane fluidity in eukaryotes. In: ICYGMB 2007: 23rd International Conference on Yeast Genetics and Molecular Biology, 1-6 Jul 2007, Melbourne, Australia.

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Abstract

The mechanisms which control the fluidity of eukaryotic membranes are unknown. We have identified S. cerevisiae deletion strains whose growth is impaired by palmitoleic (PO; C16:1) but not oleic (C18:1) acid. PO-sensitivity is suppressed by oleate thus perhaps identifying a signaling pathway that controls the ratio of these fatty acids in membrane phospholipid. Growth of these mutants is also inhibited by a known fluidizer, benzyl alcohol, thus indicating that PO has a fluidizing effect. Removal of Pkc1, known to play a key role in cell wall integrity control, leads to acute PO-sensitivity. Removal of Bck1, Mkk1, Mkk2, Slt2, or Swi6 downstream components of the cell wall integrity pathway, cause modest POsensitivity. Suppression by 1M sorbitol of the PO-sensitivity of these four mutants implies that PO/oleate ratio influences the cell wall. Acute PO-sensitivity of the pkc1Δ strain, even in the presence of 1M sorbitol, suggests the cell wall to be more severely compromised by PO addition to this strain. Alternatively, the failure to control the PO/oleate ratio could have an additional effect on the pkc1 strain, perhaps by disabling a 2nd pathway downstream of Pkc1 thus allowing PO addition to cause excess membrane fluidity. We are attempting to distinguish these two models by a variety of genetic, biochemical, and physical methods. Most notably, the effect of PO on the fluidity of the plasma membrane is being examined by measuring the depolarization of laurdan fluorescence.


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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Paper)
Refereed: No
Item Status: Live Archive
Additional Information: Abstract only. Awaiting full paper from authors.
Depositing User: Ms Debbie White
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 11 Oct 2007 01:19
Last Modified: 02 Jul 2013 22:48
Uncontrolled Keywords: eukaryotic membranes; palmitoleic acid
Fields of Research (FOR2008): 06 Biological Sciences > 0601 Biochemistry and Cell Biology > 060110 Receptors and Membrane Biology
06 Biological Sciences > 0601 Biochemistry and Cell Biology > 060106 Cellular Interactions (incl. Adhesion, Matrix, Cell Wall)
06 Biological Sciences > 0605 Microbiology > 060503 Microbial Genetics
Socio-Economic Objective (SEO2008): E Expanding Knowledge > 97 Expanding Knowledge > 970106 Expanding Knowledge in the Biological Sciences
URI: http://eprints.usq.edu.au/id/eprint/3017

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