The Ursinus Weekly, October 17, 1949

Millers contribute two chapters to volume in honor of Blakeslee • Bears seek victory over Garnet eleven in traditional fray • Soccer team drops season opener 4-0 to Castle Pointers • Booters select Peterson; Frick leads coed squad • Dickinson runs wild in easy 35-0 triumph • Curtis tops league in campus football; Ping pong to start • Gurzynski discloses cross-country slate • Popular pair views life south of the Rio Grande • Verve and style of \u2751ers maintain famed tradition of Glenwood quartet • Freshmen elect George Ott president • Frosh cuties massacre burlesque • Students hold rites for departed spirit • Actors\u27 club slates Shaw\u27s Pygmalion • Seniors name date for annual dance • Speaker prescribes change in policies for U.S. with Asia • Penn prexy will address Founders\u27 Day audience • Observatory proves valuable addition to science building • Y cabinet schedules Green Lane retreat for this week-end • Chairman explains current regulations to campus leaders • Ruby editors announce selection of staff heads for \u2750 edition • Literary publication adds five editors to masthead • Sororities prepare for rushing; Sophs to receive bids Fridayhttps://digitalcommons.ursinus.edu/weekly/1573/thumbnail.jp

Extracellular signal-regulated kinase 1/2 activity is not required in mammalian cells during late G2 for timely entry into or exit from mitosis

Author Posting. © American Society for Cell Biology, 2006. This article is posted here by permission of American Society for Cell Biology for personal use, not for redistribution. The definitive version was published in Molecular Biology of the Cell 17 (2006): 5227-5240, doi:10.1091/mbc.E06-04-0284.Extracellular signal-regulated kinase (ERK)1/2 activity is reported to be required in mammalian cells for timely entry into and exit from mitosis (i.e., the G2-mitosis [G2/M] and metaphase-anaphase [M/A] transitions). However, it is unclear whether this involvement reflects a direct requirement for ERK1/2 activity during these transitions or for activating gene transcription programs at earlier stages of the cell cycle. To examine these possibilities, we followed live cells in which ERK1/2 activity was inhibited through late G2 and mitosis. We find that acute inhibition of ERK1/2 during late G2 and through mitosis does not affect the timing of the G2/M or M/A transitions in normal or transformed human cells, nor does it impede spindle assembly, inactivate the p38 stress-activated checkpoint during late G2 or the spindle assembly checkpoint during mitosis. Using CENP-F as a marker for progress through G2, we also show that sustained inhibition of ERK1/2 transiently delays the cell cycle in early/mid-G2 via a p53-dependent mechanism. Together, our data reveal that ERK1/2 activity is required in early G2 for a timely entry into mitosis but that it does not directly regulate cell cycle progression from late G2 through mitosis in normal or transformed mammalian cells.This research was supported by National Institutes of Health Grant GMS-40198 to C.L.R., by National Institutes of Health/National Cancer Institute Grant CA109182, and Samuel Waxman Cancer Research Foundation grants to J.A.A.-G

On the Roles of Substrate Binding and Hinge Unfolding in Conformational Changes of Adenylate Kinase

We characterized the conformational change of adenylate kinase (AK) between open and closed forms by conducting five all-atom molecular-dynamics simulations, each of 100 ns duration. Different initial structures and substrate binding configurations were used to probe the pathways of AK conformational change in explicit solvent, and no bias potential was applied. A complete closed-to-open and a partial open-to-closed transition were observed, demonstrating the direct impact of substrate-mediated interactions on shifting protein conformation. The sampled configurations suggest two possible pathways for connecting the open and closed structures of AK, affirming the prediction made based on available x-ray structures and earlier works of coarse-grained modeling. The trajectories of the all-atom molecular-dynamics simulations revealed the complexity of protein dynamics and the coupling between different domains during conformational change. Calculations of solvent density and density fluctuations surrounding AK did not show prominent variation during the transition between closed and open forms. Finally, we characterized the effects of local unfolding of an important hinge near Pro177 on the closed-to-open transition of AK and identified a novel mechanism by which hinge unfolding modulates protein conformational change. The local unfolding of Pro177 hinge induces alternative tertiary contacts that stabilize the closed structure and prevent the opening transition