Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


osu1343763753.pdf (14.8 MB)

ETD Abstract Container

Abstract Header

Targeting of Peripherally Associated Proteins to the Inner Nuclear Membrane in Saccharomyces cerevisiae: The Role of Essential Proteins

Diaz, Greetchen M.
http://rave.ohiolink.edu/etdc/view?acc_num=osu1343763753

Abstract Details

2012, Doctor of Philosophy, Ohio State University, Molecular, Cellular and Developmental Biology.
The nuclear envelope (NE) is composed of the inner nuclear membrane (INM) and the outer nuclear membrane (ONM) which is contiguous with the endoplasmic reticulum (ER). The appropriate location of NE proteins is important in cells. Integral INM proteins are proposed to be synthesized at the ER and then translocated through the nuclear pore complex (NPC). In contrast, peripherally associated INM proteins are proposed to follow a targeting mechanism to the nucleus that is similar to nucleoplasmic proteins. Our research aims to understand the mechanism of targeting of peripherally associated proteins to the INM. We employed yeast as a genetic model and the tRNA modification enzyme, Trm1-II, as a reporter. We screened a collection of temperature sensitive (ts) mutants for defects in galactose-inducible Trm1-II-GFP (Gal-Trm1-II-GFP) INM localization. We found that the majority (46%) of the ts mutations affecting Gal-Trm1-II-GFP localization were in genes that encode proteins involved in ER-Golgi homeostasis. Interestingly, about 35% of the mutated essential genes encode components of the Spindle Pole Body (SPB). In the SPB ts mutants, at the non-permissive temperature, Gal-Trm1-II-GFP accumulates as a spot that localizes to the ER, rather than being evenly distributed around the entire INM as in wild-type cells. Following the dynamics of Gal-Trm1-II-GFP we learned that its inappropriate distribution results from a failure to move from the initial contact with the NE (ONM) throughout the INM. Gal-Trm1-GFP accumulates to the ER with time, suggesting that this might be the initial Trm1-II tethering site. Surprisingly, SPB defects also affect targeting of an integral INM protein, but not a soluble nucleoplasmic protein which indicates that there is no defect in import and that appropriate SPBs are required for INM targeting of both integral and peripheral INM proteins, but not nucleoplasmic proteins. Our evidence suggests Gal-Trm1-II-GFP is alternatively transported via soluble mechanism when unable to tether to the ER. We propose a novel mechanism for peripherally associated INM proteins that combines targeting mechanisms for both integral and soluble proteins. We also learned that INM maintenance of Gal-Trm1-II-GFP was altered in SPB defective cells, which suggests that a general defect at the membrane that forms the ER and the NE occurs in SPB defective cells. The possible role of the SPB based in INM targeting and maintenance is discussed.
Anita K. Hopper, PhD (Advisor)
Stephen Osmani, PhD (Committee Member)
Mark Parthun, PhD (Committee Member)
Jian-Qiu Wu, PhD (Committee Member)
214 p.
Genetics
yeast; inner nuclear membrane; protein targeting; spindle pole body; peripheral protein; essential genes

Recommended Citations

Citations

  • Diaz, G. M. (2012). Targeting of Peripherally Associated Proteins to the Inner Nuclear Membrane in Saccharomyces cerevisiae: The Role of Essential Proteins [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343763753

    APA Style (7th edition)

  • Diaz, Greetchen. Targeting of Peripherally Associated Proteins to the Inner Nuclear Membrane in Saccharomyces cerevisiae: The Role of Essential Proteins. 2012. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1343763753.

    MLA Style (8th edition)

  • Diaz, Greetchen. "Targeting of Peripherally Associated Proteins to the Inner Nuclear Membrane in Saccharomyces cerevisiae: The Role of Essential Proteins." Doctoral dissertation, Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343763753

    Chicago Manual of Style (17th edition)

osu1343763753
620
© 2012, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.