Abstract
Eukaryotic cells house mesoscopic and macroscopic complex systems that work in tandem for proper cellular function. A defining feature of eukaryotic cells is their mesoscopic network of membrane bound compartments called organelles. While each type of organelle has their own individual functions, there are vital cellular processes that come from the interactions between them, such as organelle biogenesis and metabolic regulation. A central question in cellular biophysics is to what degree is cellular function robust or fragile to breaks in the organelle network. These interactions can be explored by genetically deleting inter-organelle protein tethers called organelle contact sites. Here we examine this question focusing on organelle contact sites focused on the endoplasmic reticulum, a principal player in both lipid and protein synthesis in the cell. Specifically, we examine components of the OCS connecting the ER and plasma membrane, Scs2 and Scs22, as well as the ER/nuclear envelope and vacuole, Nvj1. Using hyperspectral confocal microscopy, mass spectrometry and RNA-sequencing, I aim to address the systems-level role organelle interactions have at multimodal scales. In both replete conditions and lower carbon availability, the mutant strains show insensitivity on a cellular level, yet form putative compensatory modes at the mesoscopic and microscopic scales. The organelle-scale level shows widespread changes to the endomembrane system with varying volume fractions of the endoplasmic reticulum, lipid droplets and Golgi compared to wildtype. Preliminary results from computational genome-scale metabolic models paired with mass spectrometry and RNA- sequencing experimental data support a model of lipid redirection from the endoplasmic reticulum that the organelle network works to process metabolically to maintain cellular-scale homeostasis.
Committee Chair
Shankar Mukherji
Committee Members
Anders Carlsson; Gary Patti; Mikhail Tikhonov; Ralf Wessel
Degree
Doctor of Philosophy (PhD)
Author's Department
Physics
Document Type
Dissertation
Date of Award
8-15-2025
Language
English (en)
DOI
https://doi.org/10.7936/r12t-3a70
Author's ORCID
https://orcid.org/0009-0008-9303-4168
Recommended Citation
Arra, Aline, "Multimodal Characterization of Systems-Level Robustness in the Cellular Organelle Network" (2025). Arts & Sciences Theses and Dissertations. 3574.
The definitive version is available at https://doi.org/10.7936/r12t-3a70