Graphical representation of blood group data of human populations

A general survey of various measures of diversity within and distance between populations in gene frequencies of blood group systems is given. A method of ordering populations by an overall measure of diversity within and of clustering populations in terms of differences in pattern of diversity in different blood group systems is developed. Principal coordinate analysis and multidimensional scaling are used to represent populations with given distances between them graphically in an appropriate dimensional Euclidean space. Such graphical representations together with dendrograms are of great help in studying interrelationships between populations. The methods are illustrated using blood group data on some human populations

Investigation of LKB1 Ser⁴³¹ phosphorylation and Cys⁴³³ farnesylation using mouse knockin analysis reveals an unexpected role of prenylation in regulating AMPK activity

The LKB1 tumour suppressor protein kinase functions to activate two isoforms of AMPK (AMP-activated protein kinase) and 12 members of the AMPK-related family of protein kinases. The highly conserved C-terminal residues of LKB1 are phosphorylated (Ser(431)) by PKA (cAMP-dependent protein kinase) and RSK (ribosomal S6 kinase) and farnesylated (Cys(433)) within a CAAX motif. To better define the role that these post-translational modifications play, we created homozygous LKB1(S431A/S431A) and LKB1(C433S/C433S) knockin mice. These animals were viable, fertile and displayed no overt phenotypes. Employing a farnesylation-specific monoclonal antibody that we generated, we established by immunoprecipitation that the vast majority, if not all, of the endogenous LKB1 is prenylated. Levels of LKB1 localized at the membrane of the liver of LKB1(C433S/C433S) mice and their fibroblasts were reduced substantially compared with the wild-type mice, confirming that farnesylation plays a role in mediating membrane association. Although AMPK was activated normally in the LKB1(S431A/S431A) animals, we unexpectedly observed in all of the examined tissues and cells taken from LKB1(C433S/C433S) mice that the basal, as well as that induced by the AMP-mimetic AICAR (5-amino-4-imidazolecarboxamide riboside), AMPK activation, phenformin and muscle contraction were significantly blunted. This resulted in a reduced ability of AICAR to inhibit lipid synthesis in primary hepatocytes isolated from LKB1(C433S/C433S) mice. The activity of several of the AMPK-related kinases analysed [BRSK1 (BR serine/threonine kinase 1), BRSK2, NUAK1 (NUAK family, SNF1-like kinase 1), SIK3 (salt-inducible kinase 3) and MARK4 (MAP/microtubule affinity-regulating kinase 4)] was not affected in tissues derived from LKB1(S431A/S431A) or LKB1(C433S/C433S) mice. Our observations reveal for the first time that farnesylation of LKB1 is required for the activation of AMPK. Previous reports have indicated that a pool of AMPK is localized at the plasma membrane as a result of myristoylation of its regulatory AMPKβ subunit. This raises the possibility that LKB1 farnesylation and myristoylation of AMPKβ might promote the interaction and co-localization of these enzymes on a two-dimensional membrane surface and thereby promote efficient activation of AMPK

Patterning Bacterial Communities on Epithelial Cells

Micropatterning of bacteria using aqueous two phase system (ATPS) enables the localized culture and formation of physically separated bacterial communities on human epithelial cell sheets. This method was used to compare the effects of Escherichia coli strain MG1655 and an isogenic invasive counterpart that expresses the invasin (inv) gene from Yersinia pseudotuberculosis on the underlying epithelial cell layer. Large portions of the cell layer beneath the invasive strain were killed or detached while the non-invasive E. coli had no apparent effect on the epithelial cell layer over a 24 h observation period. In addition, simultaneous testing of the localized effects of three different bacterial species; E. coli MG1655, Shigella boydii KACC 10792 and Pseudomonas sp DSM 50906 on an epithelial cell layer is also demonstrated. The paper further shows the ability to use a bacterial predator, Bdellovibrio bacteriovorus HD 100, to selectively remove the E. coli, S. boydii and P. sp communities from this bacteria-patterned epithelial cell layer. Importantly, predation and removal of the P. Sp was critical for maintaining viability of the underlying epithelial cells. Although this paper focuses on a few specific cell types, the technique should be broadly applicable to understand a variety of bacteria-epithelial cell interactionsopen3

MO25 is a master regulator of SPAK/OSR1 and MST3/MST4/YSK1 protein kinases

This paper from the Alessi lab identifies the LKB-activator complex component MO25 as master-regulator of multiple Ste20 kinases. Starting from a structural template, biochemical and initial functional assays reveal MO25 as potential physiological regulator of NKCC kidney ion cotransporter

Interpretive asymmetries, diagnostic inquiry and the reconstruction of action in an incident of friendly fire

In this article, we examine a controversial friendly fire incident that took place during the early stages of the Iraq war. Our focus is on how a cockpit video of the incident was used post facto in a military inquiry to arrive at an understanding of the actions of the pilots involved. We shall concentrate specifically on a series of interpretive difficulties that highlighted the problematic status of the video as evidence and explore what their resolution might tell us about military practice, and the place of friendly fire within it more broadly

Identification of protor as a novel rictor-binding component of mTOR complex-2

The mTOR (mammalian target of rapamycin) protein kinase is an important regulator of cell growth. Two complexes of mTOR have been identified: complex 1, consisting of mTOR–Raptor (regulatory associated protein of mTOR)–mLST8 (termed mTORC1), and complex 2, comprising mTOR–Rictor (rapamycininsensitive companion of mTOR)–mLST8–Sin1 (termed mTORC2). mTORC1 phosphorylates the p70 ribosomal S6K (S6 kinase) at its hydrophobic motif (Thr389), whereas mTORC2 phosphorylates PKB (protein kinase B) at its hydrophobic motif (Ser<sup>473</sup>). In the present study, we report that widely expressed isoforms of unstudied proteins termed Protor-1 (protein observed with Rictor-1) and Protor-2 interact with Rictor and are components of mTORC2. We demonstrate that immunoprecipitation of Protor-1 or Protor-2 results in the co-immunoprecipitation of other mTORC2 subunits, but not Raptor, a specific component of mTORC1. We show that detergents such as Triton X-100 or n-octylglucoside dissociate mTOR and mLST8 from a complex of Protor-1, Sin1 and Rictor. We also provide evidence that Rictor regulates the expression of Protor-1, and that Protor-1 is not required for the assembly of other mTORC2 subunits into a complex. Protor-1 is a novel Rictor-binding subunit of mTORC2, but further work is required to establish its role