Publications by authors named "Allan Bruce Downie"

2 Publications

  • Page 1 of 1

Late Embryogenesis Abundant Protein-Client Protein Interactions.

Plants (Basel) 2020 Jun 29;9(7). Epub 2020 Jun 29.

Department of Horticulture, University of Kentucky Seed Biology Program, Plant Science Building, 1405 Veterans Drive, University of Kentucky, Lexington, KY 40546-0312, USA.

The intrinsically disordered proteins belonging to the LATE EMBRYOGENESIS ABUNDANT protein (LEAP) family have been ascribed a protective function over an array of intracellular components. We focus on how LEAPs may protect a stress-susceptible proteome. These examples include instances of LEAPs providing a shield molecule function, possibly by instigating liquid-liquid phase separations. Some LEAPs bind directly to their client proteins, exerting a holdase-type chaperonin function. Finally, instances of LEAP-client protein interactions have been documented, where the LEAP modulates (interferes with) the function of the client protein, acting as a surreptitious rheostat of cellular homeostasis. From the examples identified to date, it is apparent that client protein modulation also serves to mitigate stress. While some LEAPs can physically bind and protect client proteins, some apparently bind to assist the degradation of the client proteins with which they associate. Documented instances of LEAP-client protein binding, even in the absence of stress, brings to the fore the necessity of identifying how the LEAPs are degraded post-stress to render them innocuous, a first step in understanding how the cell regulates their abundance.
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http://dx.doi.org/10.3390/plants9070814DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7412488PMC
June 2020

Identification of Late Embryogenesis Abundant (LEA) protein putative interactors using phage display.

Int J Mol Sci 2012 29;13(6):6582-603. Epub 2012 May 29.

Department of Horticulture, University of Kentucky, Lexington, KY 40546-0312, USA; E-Mails: (R.K.); (T.D.L.); (K.R.S.); (S.K.).

Arabidopsis thaliana seeds without functional SEED MATURATION PROTEIN1 (SMP1), a boiling soluble protein predicted to be of intrinsic disorder, presumed to be a LATE EMBRYOGENESIS ABUNDANT (LEA) family protein based on sequence homology, do not enter secondary dormancy after 3 days at 40 °C. We hypothesized that SMP1 may protect a heat labile protein involved in the promotion of secondary dormancy. Recombinant SMP1 and GmPM28, its soybean (Glycine max), LEA4 homologue, protected the labile GLUCOSE-6-PHOSPHATE DEHYROGENASE enzyme from heat stress, as did a known protectant, Bovine Serum Albumin, whether the LEA protein was in solution or attached to the bottom of microtiter plates. Maintenance of a biological function for both recombinant LEA proteins when immobilized encouraged a biopanning approach to screen for potential protein interactors. Phage display with two Arabidopsis seed, T7 phage, cDNA libraries, normalized for transcripts present in the mature, dehydrated, 12-, 24-, or 36-h imbibed seeds, were used in biopans against recombinant SMP1 and GmPM28. Phage titer increased considerably over four rounds of biopanning for both LEA proteins, but not for BSA, at both 25 and at 41 °C, regardless of the library used. The prevalence of multiple, independent clones encoding portions of specific proteins repeatedly retrieved from different libraries, temperatures and baits, provides evidence suggesting these LEA proteins are discriminating which proteins they protect, a novel finding. The identification of putative LEA-interacting proteins provides targets for reverse genetic approaches to further dissect the induction of secondary dormancy in seeds in response to heat stress.
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http://dx.doi.org/10.3390/ijms13066582DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3397483PMC
September 2015