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Articles 1 - 9 of 9

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Megadalton-Node Assembly By Binding Of Skb1 To The Membrane Anchor Slf1, Lin L. Deng, Ruth Kabeche, Ning Wang, Jian-Qiu Wu, James B. Moseley Jul 2014

Megadalton-Node Assembly By Binding Of Skb1 To The Membrane Anchor Slf1, Lin L. Deng, Ruth Kabeche, Ning Wang, Jian-Qiu Wu, James B. Moseley

Open Dartmouth: Faculty Open Access Scholarship

The plasma membrane contains both dynamic and static microdomains. Given the growing appreciation of cortical microdomains in cell biology, it is important to determine the organizational principles that underlie assembly of compartmentalized structures at the plasma membrane. The fission yeast plasma membrane is highly compartmentalized by distinct sets of cortical nodes, which control signaling for cell cycle progression and cytokinesis. The mitotic inhibitor Skb1 localizes to a set of cortical nodes that provide spatial control over signaling for entry into mitosis. However, it has been unclear whether these nodes contain other proteins and how they might be organized and tethered ...


Septin Assemblies Form By Diffusion-Driven Annealing On Membranes, Andrew A. Bridges, Huaiying Zhang, Shalin B. Mehta, Patricia Occhipinti, Tomomi Tani, Amy S. Gladfelter Feb 2014

Septin Assemblies Form By Diffusion-Driven Annealing On Membranes, Andrew A. Bridges, Huaiying Zhang, Shalin B. Mehta, Patricia Occhipinti, Tomomi Tani, Amy S. Gladfelter

Open Dartmouth: Faculty Open Access Scholarship

Septins assemble into filaments and higher-order structures that act as scaffolds for diverse cell functions including cytokinesis, cell polarity, and membrane remodeling. Despite their conserved role in cell organization, little is known about how septin filaments elongate and are knitted together into higher-order assemblies. Using fluorescence correlation spectroscopy, we determined that cytosolic septins are in small complexes, suggesting that septin filaments are not formed in the cytosol. When the plasma membrane of live cells is monitored by total internal reflection fluorescence microscopy, we see that septin complexes of variable size diffuse in two dimensions. Diffusing septin complexes collide and make ...


Killerflip: A Novel Lytic Peptide Specifically Inducing Cancer Cell Death, B Pennarun, G. Gaidos, O Bucur, A Tinari Oct 2013

Killerflip: A Novel Lytic Peptide Specifically Inducing Cancer Cell Death, B Pennarun, G. Gaidos, O Bucur, A Tinari

Open Dartmouth: Faculty Open Access Scholarship

One of the objectives in the development of effective cancer therapy is induction of tumor-selective cell death. Toward this end, we have identified a small peptide that, when introduced into cells via a TAT cell-delivery system, shows a remarkably potent cytoxicity in a variety of cancer cell lines and inhibits tumor growth in vivo, whereas sparing normal cells and tissues. This fusion peptide was named killer FLIP as its sequence was derived from the C-terminal domain of c-FLIP, an anti-apoptotic protein. Using structure activity analysis, we determined the minimal bioactive core of killerFLIP, namely killerFLIP-E. Structural analysis of cells using ...


Alginate Lyase Exhibits Catalysis-Independent Biofilm Dispersion And Antibiotic Synergy, John W. Lamppa, Karl E. Griswold Jan 2013

Alginate Lyase Exhibits Catalysis-Independent Biofilm Dispersion And Antibiotic Synergy, John W. Lamppa, Karl E. Griswold

Open Dartmouth: Faculty Open Access Scholarship

More than 2 decades of study support the hypothesis that alginate lyases are promising therapeutic candidates for treating mucoid Pseudomonas aeruginosa infections. In particular, the enzymes' ability to degrade alginate, a key component of mucoid biofilm matrix, has been the presumed mechanism by which they disrupt biofilms and enhance antibiotic efficacy. The systematic studies reported here show that, in an in vitro model, alginate lyase dispersion of P. aeruginosa biofilms and enzyme synergy


Requirements For Transitional Endoplasmic Reticulum Site Structure And Function In Saccharomyces Cerevisiae, Polina Shindiapina, Charles Barlowe Feb 2010

Requirements For Transitional Endoplasmic Reticulum Site Structure And Function In Saccharomyces Cerevisiae, Polina Shindiapina, Charles Barlowe

Open Dartmouth: Faculty Open Access Scholarship

Secretory proteins are exported from the endoplasmic reticulum (ER) at specialized regions known as the transitional ER (tER). Coat protein complex II (COPII) proteins are enriched at tER sites, although the mechanisms underlying tER site assembly and maintenance are not understood. Here, we investigated the dynamic properties of tER sites in Saccharomyces cerevisiae and probed protein and lipid requirements for tER site structure and function. Thermosensitive sec12 and sec16 mutations caused a collapse of tER sites in a manner that depended on nascent secretory cargo. Continual fatty acid synthesis was required for ER export and for normal tER site structure ...


Examining The Link Between Chromosomal Instability And Aneuploidy In Human Cells, Sarah L. Thompson, Duane A. Compton Jan 2008

Examining The Link Between Chromosomal Instability And Aneuploidy In Human Cells, Sarah L. Thompson, Duane A. Compton

Open Dartmouth: Faculty Open Access Scholarship

Solid tumors can be highly aneuploid and many display high rates of chromosome missegregation in a phenomenon called chromosomal instability (CIN). In principle, aneuploidy is the consequence of CIN, but the relationship between CIN and aneuploidy has not been clearly defined. In this study, we use live cell imaging and clonal cell analyses to evaluate the fidelity of chromosome segregation in chromosomally stable and unstable human cells. We show that improper microtubule–chromosome attachment (merotely) is a cause of chromosome missegregation in unstable cells and that increasing chromosome missegregation rates by elevating merotely during consecutive mitoses generates CIN in otherwise ...


A Role For Yip1p In Copii Vesicle Biogenesis, Matthew Heidtman, Catherine Z. Chen, Ruth N. Collins, Charles Barlowe Oct 2003

A Role For Yip1p In Copii Vesicle Biogenesis, Matthew Heidtman, Catherine Z. Chen, Ruth N. Collins, Charles Barlowe

Open Dartmouth: Faculty Open Access Scholarship

Yeast Ypt1p-interacting protein (Yip1p) belongs to a conserved family of transmembrane proteins that interact with Rab GTPases. We encountered Yip1p as a constituent of ER-derived transport vesicles, leading us to hypothesize a direct role for this protein in transport through the early secretory pathway. Using a cell-free assay that recapitulates protein transport from the ER to the Golgi complex, we find that affinity-purified antibodies directed against the hydrophilic amino terminus of Yip1p potently inhibit transport. Surprisingly, inhibition is specific to the COPII-dependent budding stage. In support of this in vitro observation, strains bearing the temperature-sensitive yip1-4 allele accumulate ER membranes ...


Minus-End Capture Of Preformed Kinetochore Fibers Contributes To Spindle Morphogenesis, Alexey Khodjakov, Lily Copenagle, Michael B. Gordon, Duane A. Compton, Tarun M. Kapoor Mar 2003

Minus-End Capture Of Preformed Kinetochore Fibers Contributes To Spindle Morphogenesis, Alexey Khodjakov, Lily Copenagle, Michael B. Gordon, Duane A. Compton, Tarun M. Kapoor

Open Dartmouth: Faculty Open Access Scholarship

Near-simultaneous three-dimensional fluorescence/differential interference contrast microscopy was used to follow the behavior of microtubules and chromosomes in living alpha-tubulin/GFP-expressing cells after inhibition of the mitotic kinesin Eg5 with monastrol. Kinetochore fibers (K-fibers) were frequently observed forming in association with chromosomes both during monastrol treatment and after monastrol removal. Surprisingly, these K-fibers were oriented away from, and not directly connected to, centrosomes and incorporated into the spindle by the sliding of their distal ends toward centrosomes via a NuMA-dependent mechanism. Similar preformed K-fibers were also observed during spindle formation in untreated cells. In addition, upon monastrol removal, centrosomes established ...


Docking Of Yeast Vacuoles Is Catalyzed By The Ras-Like Gtpase Ypt7p After Symmetric Priming By Sec18p (Nsf), Andreas Mayer, William Wickner Jan 1997

Docking Of Yeast Vacuoles Is Catalyzed By The Ras-Like Gtpase Ypt7p After Symmetric Priming By Sec18p (Nsf), Andreas Mayer, William Wickner

Open Dartmouth: Faculty Open Access Scholarship

Vacuole inheritance in yeast involves the for- mation of tubular and vesicular “segregation struc- tures” which migrate into the bud and fuse there to es- tablish the daughter cell vacuole. Vacuole fusion has been reconstituted in vitro and may be used as a model for an NSF-dependent reaction of priming, docking, and fusion. We have developed biochemical and micro- scopic assays for the docking step of in vitro vacuole fusion and characterized its requirements. The vacu- oles must be primed for docking by the action of Sec17p ( a -SNAP) and Sec18p (NSF). Priming is neces- sary for both fusion partners ...