skip to main content


Title: BRXL4‐LAZY1 interaction at the plasma membrane controls Arabidopsis branch angle and gravitropism
Award ID(s):
2124689
PAR ID:
10418193
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
The Plant Journal
Volume:
113
Issue:
2
ISSN:
0960-7412
Page Range / eLocation ID:
211 to 224
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract

    We describe sloth assemblages from theCocinetasBasin (LaGuajira peninsula,Colombia), found in theNeogeneCastilletes andWare formations, located in northernmostSouthAmerica, documenting otherwise poorly known biotas. The tentative referral of a specimen to a small megatherioid sloth,Hyperleptus?, from the early–middleMioceneCastilletesFormation, suggests affinities of this fauna with the distantSantaCruzFormation and documents a large latitudinal distribution for this taxon. The latePlioceneWareFormation is much more diverse, with five distinct taxa representing every family of ‘ground sloths’. This diversity is also remarkable at the ecological level, with sloths spanning over two orders of magnitude of body mass and probably having different feeding strategies. Being only a few hundred kilometres away from theIsthmus ofPanama, and a few hundred thousand years older than the classically recognized first main pulse of theGreatAmericanBiotic interchange (GABI1), theWareFormation furthermore documents an important fauna for the understanding of this major event inNeogene palaeobiogeography. The sloths for which unambiguous affinities were recovered are not closely related to the early immigrants found inNorthAmerica beforeGABI1.

     
    more » « less
  2. Abstract

    We present differential Strömgrenuvbyobservations from the Four College Automated Photometric Telescope (FCAPT) in Washington Camp, AZ of eight magnetic Chemically Peculiar (mCP) stars: HD 32966, HD 35298, HD 68292, HD 93226, HD 171247, HD 217833, HD 220147, and HD 223358. We use multiple period‐finding algorithms and incorporate data from the ESA Hipparcos catalogue to study the amplitudes, periods, and asymmetries in the light curves. No previous FCAPT data have been published for HD 68292. For the seven other stars, these studies substantially extend the analyses of published FCAPT datasets.

     
    more » « less
  3. Abstract

    Structure and functions of S100 proteins are regulated by two distinct calcium binding EF hand motifs. In this work, we used solution‐state NMR spectroscopy to investigate the cooperativity between the two calcium binding sites and map the allosteric changes at the target binding site. To parse the contribution of the individual calcium binding events, variants of S100A12 were designed to selectively bind calcium to either the EF‐I (N63A) or EF‐II (E31A) loop, respectively. Detailed analysis of the backbone chemical shifts for wildtype protein and its mutants indicates that calcium binding to the canonical EF‐II loop is the principal trigger for the conformational switch between ‘closed’ apo to the ‘open’ Ca2+‐bound conformation of the protein. Elimination of binding in S100‐specific EF‐I loop has limited impact on the calcium binding affinity of the EF‐II loop and the concomitant structural rearrangement. In contrast, deletion of binding in the EF‐II loop significantly attenuates calcium affinity in the EF‐I loop and the structure adopts a ‘closed’ apo‐like conformation. Analysis of experimental amide nitrogen (15N) relaxation rates (R1,R2, and15N–{1H} NOE) and molecular dynamics (MD) simulations demonstrate that the calcium bound state is relatively floppy with pico–nanosecond motions induced in functionally relevant domains responsible for target recognition such as the hinge domain and the C‐terminal residues. Experimental relaxation studies combined with MD simulations show that while calcium binding in the EF‐I loop alone does not induce significant motions in the polypeptide chain, EF‐I regulates fluctuations in the polypeptide in the presence of bound calcium in the EF‐II loop. These results offer novel insights into the dynamic regulation of target recognition by calcium binding and unravels the role of cooperativity between the two calcium binding events in S100A12.

     
    more » « less
  4. Summary

    The mitochondrial and chloroplastmRNAs of the majority of land plants are modified through cytidine to uridine (C‐to‐U)RNAediting. Previously, forward and reverse genetic screens demonstrated a requirement for pentatricopeptide repeat (PPR) proteins forRNAediting. Moreover, chloroplast editing factorsOZ1,RIP2,RIP9 andORRM1 were identified in co‐immunoprecipitation (co‐IP) experiments, albeit the minimal complex sufficient for editing activity was never deduced. The current study focuses on isolated, intact complexes that are capable of editing distinct sites. Peak editing activity for four sites was discovered in size‐exclusion chromatography (SEC) fractions ≥ 670 kDa, while fractions estimated to be approximately 413 kDa exhibited the greatest ability to convert a substrate containing the editing siterps14C80.RNAcontent peaked in the ≥ 670 kDa fraction. Treatment of active chloroplast extracts withRNase A abolished the relationship of editing activity with high‐MWfractions, suggesting a structuralRNAcomponent in native complexes. By immunoblotting,RIP9,OTP86,OZ1 andORRM1 were shown to be present in active gel filtration fractions, thoughOZ1 andORRM1 were mainly found in low‐MWinactive fractions. Active editing factor complexes were affinity‐purified using anti‐RIP9 antibodies, and orthologs to putativeArabidopsis thalianaRNAediting factorPPRproteins,RIP2,RIP9,RIP1,OZ1,ORRM1 andISE2 were identified via mass spectrometry. Western blots from co‐IP studies revealed the mutual association ofOTP86 andOZ1 with nativeRIP9 complexes. Thus,RIP9 complexes were discovered to be highly associated with C‐to‐URNAediting activity and other editing factors indicative of their critical role in vascular plant editosomes.

     
    more » « less