Life Sciences Commons^™

Regulation Of Rna Stability By Terminal Nucleotidyltransferases, Christina Z. Chung

Electronic Thesis and Dissertation Repository

The dysregulation of RNAs has global effects on all cellular pathways. The regulation of RNA metabolism is thus tightly controlled. Terminal RNA nucleotidyltransferases (TENTs) regulate RNA stability and activity through the addition of non-templated nucleotides to the 3′-end. TENT-catalyzed adenylation and uridylation have opposing effects; adenylation stabilizes while uridylation silences or degrades RNA. All TENT homologs were initially characterized as adenylyltransferases; the identification of caffeine-induced death suppressor protein 1 (Cid1) in Schizosaccharomyces pombe as an uridylyltransferase led to the reclassification of many TENTs as uridylyltransferases. Cid1 uridylates mRNAs that are subsequently degraded by the exonuclease Dis-like 3′-5′ exonuclease 2 (Dis3L2), …

Differentially Activating The Oncogenic Kinase Akt1, Nileeka Balasuriya

Electronic Thesis and Dissertation Repository

The proto-oncogene Akt/protein kinase B plays a pivotal role in cell growth and survival. Phosphorylation of Akt at Thr308 and Ser473 activates the kinase following growth factor stimulation. Delineating specific role of each activation site in Akt1 on kinase activation, inhibition and substrate selection remain elusive.

We designed a unique set of tools, relying on genetic code expansion with phosphoserine and in vivo enzymatic phosphorylation, to produce differentially phosphorylated Akt1 variants. We found that having both sites phosphorylated increased the apparent catalytic rate of the enzyme by 1500-fold relative to the unphosphorylated enzyme. This increment was mainly due to the …

Applications Of Phosphotyrosine Superbinding Sh2 Domain Variants, Xuguang Liu

Electronic Thesis and Dissertation Repository

Protein tyrosine kinases (PTKs, or TKs) have emerged as one of the most intensively pursued targets in the development of anti-cancer therapeutics, due to their critical roles in the phosphotyrosine (pTyr)-mediated signaling network that regulates many cancer-related cellular activities. The TKs, tyrosine phosphorylation phosphatases (PTPs) and pTyr recognition SH2 proteins are intensively tyrosine phosphorylated, which play a pivotal role in determining the signaling outcome of this network. More than 50% of all human proteins are tyrosine phosphorylated and many of these TK substrates have been proven functional in TK regulated cellular activities. Therefore, proteomics studies of tyrosine phosphorylation are of …