Medicine and Health Sciences Commons^™

Scavenger Receptor Class B Type I Regulates Cellular Cholesterol Metabolism And Cell Signaling Associated With Breast Cancer Development., Christiane Danilo, Jorge L Gutierrez-Pajares, Maria Antonietta Mainieri, Isabelle Mercier, Michael P. Lisanti, Philippe G. Frank

Department of Stem Cell Biology and Regenerative Medicine Faculty Papers & Presentations

INTRODUCTION: Previous studies have identified cholesterol as an important regulator of breast cancer development. High-density lipoprotein (HDL) and its cellular receptor, scavenger receptor class B type I (SR-BI) have both been implicated in the regulation of cellular cholesterol homeostasis, but their functions in cancer remain to be established.

METHODS: In the present study, we have examined the role of HDL and SR-BI in the regulation of cellular signaling pathways in breast cancer cell lines and in the development of tumor in a mouse xenograft model.

RESULTS: Our data show that HDL is capable of stimulating migration and can activate signal …

Possible Steps Of Complete Disassembly Of Post-Termination Complex By Yeast Eef3 Deduced From Inhibition By Translocation Inhibitors., Shinya Kurata, Ben Shen, Jun O Liu, Nono Takeuchi, Akira Kaji, Hideko Kaji

Department of Biochemistry and Molecular Biology Faculty Papers

Ribosomes, after one round of translation, must be recycled so that the next round of translation can occur. Complete disassembly of post-termination ribosomal complex (PoTC) in yeast for the recycling consists of three reactions: release of tRNA, release of mRNA and splitting of ribosomes, catalyzed by eukaryotic elongation factor 3 (eEF3) and ATP. Here, we show that translocation inhibitors cycloheximide and lactimidomycin inhibited all three reactions. Cycloheximide is a non-competitive inhibitor of both eEF3 and ATP. The inhibition was observed regardless of the way PoTC was prepared with either release factors or puromycin. Paromomycin not only inhibited all three reactions …

Dynein And Dynactin Leverage Their Bivalent Character To Form A High-Affinity Interaction., Amanda E Siglin, Shangjin Sun, Jeffrey K Moore, Sarah Tan, Martin Poenie, James D Lear, Tatyana Polenova, John A Cooper, John C Williams

Department of Biochemistry and Molecular Biology Faculty Papers

Cytoplasmic dynein and dynactin participate in retrograde transport of organelles, checkpoint signaling and cell division. The principal subunits that mediate this interaction are the dynein intermediate chain (IC) and the dynactin p150(Glued); however, the interface and mechanism that regulates this interaction remains poorly defined. Herein, we use multiple methods to show the N-terminus of mammalian dynein IC, residues 10-44, is sufficient for binding p150(Glued). Consistent with this mapping, monoclonal antibodies that antagonize the dynein-dynactin interaction also bind to this region of the IC. Furthermore, double and triple alanine point mutations spanning residues 6 to 19 in the yeast IC homolog, …

Structural Implications For Selective Targeting Of Parps., Jamin D Steffen, Md, Jonathan Brody, Md, Roger S Armen, Md, John M Pascal, Md

Department of Biochemistry and Molecular Biology Faculty Papers

Poly(ADP-ribose) polymerases (PARPs) are a family of enzymes that use NAD(+) as a substrate to synthesize polymers of ADP-ribose (PAR) as post-translational modifications of proteins. PARPs have important cellular roles that include preserving genomic integrity, telomere maintenance, transcriptional regulation, and cell fate determination. The diverse biological roles of PARPs have made them attractive therapeutic targets, which have fueled the pursuit of small molecule PARP inhibitors. The design of PARP inhibitors has matured over the past several years resulting in several lead candidates in clinical trials. PARP inhibitors are mainly used in clinical trials to treat cancer, particularly as sensitizing agents …

Molecular Determinants Of Epidermal Growth Factor Binding: A Molecular Dynamics Study., Jeffrey M Sanders, Matthew E Wampole, Mathew L. Thakur, Eric Wickstrom

Department of Biochemistry and Molecular Biology Faculty Papers

The epidermal growth factor receptor (EGFR) is a member of the receptor tyrosine kinase family that plays a role in multiple cellular processes. Activation of EGFR requires binding of a ligand on the extracellular domain to promote conformational changes leading to dimerization and transphosphorylation of intracellular kinase domains. Seven ligands are known to bind EGFR with affinities ranging from sub-nanomolar to near micromolar dissociation constants. In the case of EGFR, distinct conformational states assumed upon binding a ligand is thought to be a determining factor in activation of a downstream signaling network. Previous biochemical studies suggest the existence of both …

The Tip Of The Tail Needle Affects The Rate Of Dna Delivery By Bacteriophage P22., Justin C Leavitt, Lasha Gogokhia, Eddie B Gilcrease, Anshul Bhardwaj, Gino Cingolani, Sherwood R Casjens

Department of Biochemistry and Molecular Biology Faculty Papers

The P22-like bacteriophages have short tails. Their virions bind to their polysaccharide receptors through six trimeric tailspike proteins that surround the tail tip. These short tails also have a trimeric needle protein that extends beyond the tailspikes from the center of the tail tip, in a position that suggests that it should make first contact with the host's outer membrane during the infection process. The base of the needle serves as a plug that keeps the DNA in the virion, but role of the needle during adsorption and DNA injection is not well understood. Among the P22-like phages are needle …