The inhibition of mammary epithelial cell growth by the long isoform of Angiomotin

Indiana University-Purdue University Indianapolis (IUPUI)Mammary ductal epithelial cell growth is controlled by microenvironmental signals in serum under both normal physiological settings and during breast cancer progression. Importantly, the effects of several of these microenvironmental signals are mediated by the activities of the tumor suppressor protein kinases of the Hippo pathway. Canonically, Hippo protein kinases inhibit cellular growth through the phosphorylation and inactivation of the oncogenic transcriptional co-activator Yes-Associated Protein (YAP). This study defines an alternative mechanism whereby Hippo protein kinases induce growth arrest via the phosphorylation of the long isoform of Angiomotin (Amot130). Specifically, serum starvation is found to activate the Hippo protein kinase, Large Tumor Suppressor (LATS), which phosphorylates the adapter protein Amot130 at serine-175. Importantly, wild-type Amot130 potently inhibits mammary epithelial cell growth, unlike the Amot130 serine-175 to alanine mutant, which cannot be phosphorylated at this residue. The growth-arrested phenotype of Amot130 is likely a result of its mechanistic response to LATS signaling. Specifically, LATS activity promotes the association of Amot130 with the ubiquitin ligase Atrophin-1 Interacting Protein 4 (AIP4). As a consequence, the Amot130-AIP4 complex amplifies LATS tumor suppressive signaling by stabilizing LATS protein steady state levels via preventing AIP4-targeted degradation of LATS. Additionally, AIP4 binding to Amot130 leads to the ubiquitination and stabilization of Amot130. In turn, the Amot130-AIP4 complex signals the ubiquitination and degradation of YAP. This inhibition of YAP activity by Amot130 requires both AIP4 and the ability of Amot130 to be phosphorylated by LATS. Together, these findings significantly modify the current view that the phosphorylation of YAP by Hippo protein kinases is sufficient for YAP inhibition and cellular growth arrest. Based upon these results, the inhibition of cellular growth in the absence of serum more accurately involves the stabilization of Amot130 and LATS, which together inhibit YAP activity and mammary epithelial cell growth

Aggregation Patterns in Stressed Bacteria

We study the formation of spot patterns seen in a variety of bacterial species when the bacteria are subjected to oxidative stress due to hazardous byproducts of respiration. Our approach consists of coupling the cell density field to a chemoattractant concentration as well as to nutrient and waste fields. The latter serves as a triggering field for emission of chemoattractant. Important elements in the proposed model include the propagation of a front of motile bacteria radially outward form an initial site, a Turing instability of the uniformly dense state and a reduction of motility for cells sufficiently far behind the front. The wide variety of patterns seen in the experiments is explained as being due the variation of the details of the initiation of the chemoattractant emission as well as the transition to a non-motile phase.Comment: 4 pages, REVTeX with 4 postscript figures (uuencoded) Figures 1a and 1b are available from the authors; paper submitted to PRL

HE AMOT FAMILY OF PROTEINS BINDS AND ACTIVATES NEDD4 FAMILY LIGASES TO PROMOTE THE UBIQUITINATION OF LATS AND YAP

poster abstractAmot adaptor proteins bind and integrate signaling that controls cell po-larity and growth. All three Amot family members (Amot, AmotL1 and AmotL2) directly bind YAP; a transcriptional co-activator that controls the expression of genes involved in organ homeostasis and cell growth. Preven-tion of nuclear accumulation of YAP by either sequestration or degradation in the cytosol abolishes its transcriptional functions and is a major mechanism for growth arrest in response to cellular differentiation. This is mainly thought to be regulated by phosphorylation of YAP by the Hippo kinases LATS1/2. Recently, binding by the Amot proteins was also found to inhibit YAP by sequestering it in the cytosol through both LATS dependent and in-dependent mechanisms. This study identifies a novel mechanism whereby Amot proteins control YAP activation in a Hippo independent mechanism by coupling it to ubiquitination by Nedd4 family ligases. Amot proteins mediate the coupling of Nedd4 ligases with YAP by simultaneously binding both pro-teins via multiple PY motifs that are recognized by WW domains in both YAP and Nedd4. Binding of Nedd4 by Amot is also shown to relieve the auto-inhibition of its ligase activity. This may be a direct consequence of binding Amot or from being re-targeted in cells by Amot proteins to endosomes. Im-portantly, Amot induced ubiquitination of YAP by Nedd4 proteins is shown to enhance the residence of YAP in the nucleus and in YAP activated transcrip-tion. Taken together our data suggest that Amot couples Nedd4 family ubiq-uitin ligases with the transcriptional co-activator YAP to drive the ubiquitination and activation of YAP

Effect of HER2 Expression on NUPL2 Protein in Cervical Cancer Cells

Recurring cervical cancer patients frequently present overexpressed Human Epidermal Growth Factor Receptor 2 (HER2) protein, which promotes the growth of the cancer. Some HER2-expressing cells and cervical cancer patients have enhanced gene expression of Nucleoporin-like 2 (NUPL2). As part of the nuclear pore complex, the NUPL2 protein serves to selectively export substances from the nucleus to the cytoplasm. In this experiment, HER2 was expressed in cervical cancer cells to examine its effect on NUPL2 protein expression and localization. Interestingly, there was no difference in NUPL2 protein levels between HER2-expressing and non-expressing cells. Importantly, consistent instances of NUPL2 protein localization specific to the nucleus occurred in a large sampling of HER2-expressing cells. This is significant because it suggests a mechanism as to how HER2 promotes excessive cell growth, via changes in NUPL2 localization, potentially impacting its function and ability to selectively export substances that modulate cell growth

Lubricating Bacteria Model for Branching growth of Bacterial Colonies

Various bacterial strains (e.g. strains belonging to the genera Bacillus, Paenibacillus, Serratia and Salmonella) exhibit colonial branching patterns during growth on poor semi-solid substrates. These patterns reflect the bacterial cooperative self-organization. Central part of the cooperation is the collective formation of lubricant on top of the agar which enables the bacteria to swim. Hence it provides the colony means to advance towards the food. One method of modeling the colonial development is via coupled reaction-diffusion equations which describe the time evolution of the bacterial density and the concentrations of the relevant chemical fields. This idea has been pursued by a number of groups. Here we present an additional model which specifically includes an evolution equation for the lubricant excreted by the bacteria. We show that when the diffusion of the fluid is governed by nonlinear diffusion coefficient branching patterns evolves. We study the effect of the rates of emission and decomposition of the lubricant fluid on the observed patterns. The results are compared with experimental observations. We also include fields of chemotactic agents and food chemotaxis and conclude that these features are needed in order to explain the observations.Comment: 1 latex file, 16 jpeg files, submitted to Phys. Rev.

Rosa hybrid gene GAPC is mutated in the presence of the Rose Rosette Virus

Rose Rosette Disease (RRD) harms the global rose supply by modification of the growth and development in rose cultivar. RRD spreads via a negative-sense RNA plant virus transmitted by eriophyid mites. Importantly, there is no pre-existing knowledge about the biochemistry by which this virus debilitates roses. Here we implicate glyceraldehyde-3-phosphate dehydrogenase (GAPDH), one of the major metabolic enzymes in plants, as a possible target of the virus. Genomic DNA of the cytosolic form of the protein encoded by GAPC was extracted from both virally-infected and non-infected samples of the Rosa hybrid cultivar Rosa Tropicana. The sequence results provided several distinct differences in the GAPC gene of the non-infected rose compared to the virally-infected rose. Importantly, these modified nucleotide bases resulted in a putative protein sequence containing four unique non-conserved amino acid substitutions in the GAPDH enzyme. This study provides the first evidence of a gene impacted in virally-infected rose plants

Transitioning cell culture CURE labs from campus to online: Novel strategies for a novel time

Course-based undergraduate research experiences (CUREs) provide a way for students to gain research experience in a classroom setting. Few examples of cell culture CUREs or online CUREs exist in the literature. The Cell Biology Education Consortium (CBEC) provides a network and resources for instructors working to incorporate cell-culture based research into the classroom. In this article, we provide examples from six instructors from the CBEC network on how they structure their cell-culture CUREs and how they transitioned the labs to online in the spring semester of 2020. We intend for these examples to provide instructors with ideas for strategies to set up cell culture CUREs, how to change that design mid-term, and for creating online CUREs in the future

Polarization of Lambda^0 hyperons in nucleus-nucleus collisions at high energies

The measurement of Lambda^0 hyperons polarization in nucleus-nucleus collisions is considered as one of possible tools to study the phase transition. Fixed target and collider experiments are discussed for the case of Lambda^0's production from Au-Au central collisions at \sqrt{s_{NN}} of several GeV.Comment: 15 pages, 6 figure