Medicine and Health Sciences Commons^™

Role Of Protein Kinase C Zeta (Pkcζ) In Regulation Of Epithelial Tight Junctions, Suneet Kumar Jain

Theses and Dissertations (ETD)

Occludin is hyperphosphorylated on Ser and Thr residues in intact epithelial tight junctions. The dynamics of epithelial tight junctions appear to involve reversible phosphorylation of occludin on Ser and Thr residues. In the present study we determined the role of PKCζ in occludin phosphorylation and the dynamics of tight junctions. Inhibition of PKCζ by specific PKCζ pseudo substrate rapidly reduced TER, increased inulin permeability and induced redistribution of occludin and ZO‑1 in Caco‑2 and MDCK cell monolayers without inducing cytotoxicity. Reduced expression of PKCζ also resulted in compromised tight junction integrity. Both PKCζ pseudo substrate and reduced expression of PKCζ …

Novel Insights Into Ubiquitin-Like Protein E1-E2 Interactions, Asad Taherbhoy

Theses and Dissertations (ETD)

Posttranslational modification of macromolecules by ubiquitin-like proteins (UBLs) such as ubiquitin, Sumo and NEDD8 regulate a vast array of processes in the cell. Transfer of UBLs to their target generally occurs by a series of molecular handoffs down an E1‑E2‑E3 cascade. We are interested in understanding how E1‑E2 pairs interact and mediate UBL transfer. To this effect, we studied two E1‑E2 pairs: the Sumo pathway (Sumo utilizes a canonical E1 and E2) and the Atg8 pathway (Atg8 is a UBL involved in autophagy that utilizes a non-canonical E1‑E2 pair).

Sumo conjugation is initiated by the heterodimeric Aos1‑Uba2 E1 enzyme (in …