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Open Access Publications from the University of California

Scholarly Works (28 results)

  • Article
  • Peer Reviewed
UC Irvine Previously Published Works (1982)

Transglutaminase (TGase; R-glutaminyl-peptide:amine gamma-glutamyltransferase, EC 2.3.2.13) and ornithine decarboxylase (ODCase; L-ornithine carboxy-lyase, EC 4.1.1.17) activities were measured after the addition of retinoid analogs to Chinese hamster ovary (CHO) cells released from quiescence and Cloudman S91 (CCL 53.1) mouse melanoma cells stimulated to differentiate with alpha-melanocyte-stimulating hormone (MSH, melanotropin). In both cell culture lines, we detected a biphasic increase in TGase activity and a single peak of ODCase activity within 7 hr after release or stimulation. Retinoid analogs altered the expression of the initial TGase peak in both CHO and melanoma cells. Retinol increased the activity of TGase 1 hr after release in CHO cells, and the activity remained elevated until hr 4. A broad peak of TGase activity also occurred after the addition of alpha-difluoromethylornithine, an irreversible inhibitor of ODCase, and after addition of alpha-difluoromethylornithine plus retinol. In mouse melanoma cells, retinoic acid plus MSH markedly enhanced the activity of the initial TGase peak compared to MSH alone. Retinoic acid alone also increased TGase activity biphasically in these cells without the addition of MSH. These studies suggest that retinoid effects that increase TGase activity may alter the ODCase expression in proliferation and differentiation.

    Cover page: Retinoids increase transglutaminase activity and inhibit ornithine decarboxylase activity in Chinese hamster ovary cells and in melanoma cells stimulated to differentiate.
    • Article
    • Peer Reviewed
    UC Berkeley Previously Published Works (2010)
    The design, calibration, and testing of a borescopic quantitative imaging profiler (BQuIP) system, suitable for the insitu measurement of two components of the instantaneous velocity in high sediment concentration flows, are presented. Unlike planar quantitative imaging techniques, BQuIP has a concentration-dependent field of view, requiring detailed calibration. BQuIP is demonstrated in unidirectional sheet flow in an open channel flume with a narrow-graded sand with median diameter 0.25 mm. Acoustic velocity measurements are made in the suspension region above the BQuIP measured region yielding a continuous measurement of velocity and turbulent stress from the immobile bed to just below the free surface. The temporal history at a point reveals the sheet flow sediment velocities to be highly intermittent, and the spectra reveal a broad range of temporal scales close to −5/3 in slope for the streamwise velocity component. At its core BQuIP is a quantitative imaging technique giving it significant flexibility in terms of both the spatial and temporal analysis parameters (e.g., interrogation subwindow size and Δt, the time between images in a pair to be analyzed), allowing it to have tremendous dynamic range in terms of the velocities that can be measured.
      Cover page: An insitu borescopic quantitative imaging profiler for the measurement of high concentration sediment velocity
      • Article
      • Peer Reviewed
      UCLA Previously Published Works (2015)
      Whereas ubiquitin-dependent degrons have been characterized in some detail, how proteins may be targeted to ubiquitin-independent proteasomal degradation remains unclear. Here we show that IκBα contains an ubiquitin-independent degron whose activity is portable to heterologous proteins such as the globular protein GFP (green fluorescent protein) via a proteasome-dependent, ubiquitin-independent, non-lysosomal pathway. The ubiquitin-independent degradation signal resides in an 11-amino-acid sequence, which is not only sufficient but also required for IκBα's short half-life. Finally, we show that this degron's activity is regulated by the interaction with NFκB, which controls its solvent exposure, and we demonstrate that this regulation of the degron's activity is critical for IκBα's signaling functions.
        Cover page: A Regulated, Ubiquitin-Independent Degron in IκBα
        • Article
        • Peer Reviewed
        UC Santa Cruz Previously Published Works (2005)

        Background

        Prostate cancer (PCa) is the leading cancer related death in America. Gleason grading is currently the predominant method for prediction, with only few biomarkers available. More biomarkers, especially as they relate to cancer progression are desirable.

        Methods

        The abundance of several important proteins in prostate tissue was compared between wild-type mouse dorsal prostate and well-differentiated transgenic adenocarcinoma mouse prostate (TRAMP) mouse dorsal prostates, and between wild-type mouse dorsal prostate and poorly-differentiated TRAMP mouse tumor tissue. 2DIGE method in conjunction with MALDI-ToF and Western blots was used to determine differential expression.

        Results

        In TRAMP dorsal prostates with well-differentiated adenocarcinoma, there were few significant changes in the protein abundances compared to wild-type dorsal prostates, with the exception of increases in proliferating cell nuclear antigen (PCNA) and beta tubulin, two proteins implicated in cell proliferation, and a more than 2-fold increase in Hsp60, a protein involved in the suppression of apoptosis. In the poorly-differentiated tumors, the changes in protein abundance were substantial. While some of those changes could be related to the disappearance of stromal tissue or the appearance of epithelial tissue, other changes in protein abundance were more significant to the cancer development itself. Most notable was the overall decrease in calcium homeostasis proteins with a 10-fold decrease in calreticulin and Hsp70 and a 40-fold decrease in creatine kinase bb in the cancerous tissue.

        Conclusions

        Proteomics of TRAMP mice provide an excellent method to observe changes in protein abundance, revealing changes in pathways during cancer progression.
          Cover page: Evidence for downregulation of calcium signaling proteins in advanced mouse adenocarcinoma
          • Article
          • Peer Reviewed
          UC Davis Previously Published Works (1998)
          Gonadotropin-releasing hormone (GnRH) is a decapeptide widely known for its role in regulating reproduction by serving as a signal from the hypothalamus to pituitary gonadotropes. In addition to hypothalamic GnRH (GnRH-I), a second GnRH form (pGln-His-Trp-Ser-His-Gly-Trp-Tyr-Pro-Gly; GnRH-II) with unknown function has been localized to the midbrain of many vertebrates. We show here that a gene encoding GnRH-II is expressed in humans and is located on chromosome 20p13, distinct from the GnRH-I gene that is on 8p21-p11.2. The GnRH-II genomic and mRNA structures parallel those of GnRH-I. However, in contrast to GnRH-I, GnRH-II is expressed at significantly higher levels outside the brain (up to 30x), particularly in the kidney, bone marrow, and prostate. The widespread expression of GnRH-II suggests it may have multiple functions. Molecular phylogenetic analysis shows that this second gene is likely the result of a duplication before the appearance of vertebrates, and predicts the existence of a third GnRH form in humans and other vertebrates.
            Cover page: Second gene for gonadotropin-releasing hormone in humans
            • Article
            • Peer Reviewed
            UCSB Open Access Publishing Fund Supported Publications (2014)
              • Article
              Earlier Faculty Research (1991)

              Our modern rectilinear visual environment contains visual stimuli for which evolution has not had time to optimally shape visual processing. One such stimulus, periodic stripes, is known to lead to visual depth ambiguity. In this paper we show that postural instability, as measured by the variance of fore and aft sway, is increased by viewing such stimuli. This instability may be the precursor of falls. Designers must evaluate the visual impressions conveyed by their systems in order to avoid postural instability due to visual ambiguity.

                Cover page: Postural Stability and Stereo-Ambiguity in Man-Designed Visual Environments
                • Book
                • Peer Reviewed
                4-H, Youth and Family (includes home livestock) (2017)
                One in a series of fact sheets for 4-H and youth development professionals to use when designing a program to increase diversity in program participation.
                  Cover page: Promising Practices for Programs Serving Latino Youth
                  • Book
                  • Peer Reviewed
                  4-H, Youth and Family (includes home livestock) (2017)
                  One in a series of fact sheets for 4-H professionals and Cooperative Extension directors to use when designing a program to increase diversity in program participation.
                    Cover page: Staffing for Success
                    • Article
                    • Peer Reviewed
                    UCLA Previously Published Works (2021)
                    A cytochrome c heme protein was recently engineered to catalyze the formation of carbon-silicon bonds via carbene insertion into Si-H bonds, a reaction that was not previously known to be catalyzed by a protein. High chemoselectivity toward C-Si bond formation over competing C-N bond formation was achieved, although this trait was not screened for during directed evolution. Using computational and experimental tools, we now establish that activity and chemoselectivity are modulated by conformational dynamics of a protein loop that covers the substrate access to the iron-carbene active species. Mutagenesis of residues computationally predicted to control the loop conformation altered the protein's chemoselectivity from preferred silylation to preferred amination of a substrate containing both N-H and Si-H functionalities. We demonstrate that information on protein structure and conformational dynamics, combined with knowledge of mechanism, leads to understanding of how non-natural and selective chemical transformations can be introduced into the biological world.
                      Cover page: Origin and Control of Chemoselectivity in Cytochrome c Catalyzed Carbene Transfer into Si–H and N–H bonds
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