Life Sciences Commons^™

Toward Understanding The Mechanism Of Protein Targeting In The Chloroplast Signal Recognition Particle Pathway, Mercede Furr

Graduate Theses and Dissertations

Protein targeting is a vital cellular function. The signal recognition particle (SRP) pathway is a universally conserved targeting system present in the cytosol and used to co-translationally target many proteins to the inner membrane of prokaryotes and the endoplasmic reticulum of eukaryotes. The chloroplast has a homologous SRP system which post-translationally targets light harvesting chlorophyll binding proteins (LHCPs) to the thylakoid membrane for integration. The chloroplast SRP (cpSRP) is a heterodimer with a 54 kDa subunit equivalent to SRP54 in the canonical pathway. In addition, cpSRP contains a novel 43 kDa subunit which is a unique and irreplaceable component. cpSRP43 …

The Role Of Albino3 And The Lipid Environment In Chloroplast Signal Recognition Particle Targeting, Nathan Lewis

Graduate Theses and Dissertations

Signal recognition particles (SRPs) in pro- and eukaryotes function in cotranslational targeting of nascent poplypeptides to an SRP receptor at the target membrane. A unique chloroplast SRP (cpSRP) functions post-translationally to direct light-harvesting chlorophyll-binding proteins (LHCPs) to the receptor cpFtsY at the thylakoid membrane for LHCP insertion in a process involving the integral membrane protein Albino3 (Alb3) and requiring GTP. Work here focuses on understanding cpSRP targeting events at the thylakoid membrane, specifically those involving Alb3 and the lipid environment.

We show an interaction between the novel cpSRP subunit cpSRP43 and the soluble, stromal-exposed C terminus of Albino3 (Alb3-Cterm). We …

The Membrane Interface Of Chloroplast Signal Recognition Particle-Dependent Protein Targeting, Naomi Jane Marty

Graduate Theses and Dissertations

A novel signal recognition particle (SRP) found in the chloroplast (cpSRP) works in combination with the cpSRP receptor, cpFtsY, to facilitate the post-translational targeting of a family of nuclear-encoded thylakoid proteins to the Alb3 translocase in thylakoid membranes. Work here focused on understanding events at the membrane that take place to ensure targeting of the cpSRP-dependent substrate to Alb3. Specifically, we sought to understand the structural and functional role of membrane binding by cpFtsY, a protein that exhibits the ability to partition between the membrane (thylakoid) and soluble (stroma) phase during protein targeting. We also sought to understand whether a …