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Full-Text Articles in Life Sciences
Tyrosine Phosphorylation Based Homo-Dimerization Of Arabidopsis Rack1a Proteins Regulates Oxidative Stress Signaling Pathways In Yeast, Mercy H. Sabila, Nabanita Kundu, Deana Smalls, Hemayet Ullah
Tyrosine Phosphorylation Based Homo-Dimerization Of Arabidopsis Rack1a Proteins Regulates Oxidative Stress Signaling Pathways In Yeast, Mercy H. Sabila, Nabanita Kundu, Deana Smalls, Hemayet Ullah
Hemayet Ullah
Scaffold proteins are known as important cellular regulators that can interact with multiple proteins to modulate diverse signal transduction pathways. RACK1 (Receptor for Activated C Kinase 1) is a WD-40 type scaffold protein, conserved in eukaryotes, from Chlamydymonas to plants and humans, plays regulatory roles in diverse signal transduction and stress response pathways. RACK1 in humans has been implicated in myriads of neuropathological diseases including Alzheimer and alcohol addictions. Model plant Arabidopsis thaliana genome maintains three different RACK1 genes termed RACK1A, RACK1B, and RACK1C with a very high (85-93%) sequence identity between them. Loss of function mutant in Arabidopsis indicates …
The Receptor For Activated C Kinase In Plant Signaling: Tale Of A Promiscuous Little Molecule, Tania Islas-Flores, Ahasanur Rahman, Hemayet Ullah, Marco A. Villanueva
The Receptor For Activated C Kinase In Plant Signaling: Tale Of A Promiscuous Little Molecule, Tania Islas-Flores, Ahasanur Rahman, Hemayet Ullah, Marco A. Villanueva
Hemayet Ullah
Two decades after the first report of the plant homolog of the Receptor for Activated C Kinase 1 (RACK1) in cultured tobacco BY2 cells, a significant advancement has been made in the elucidation of its cellular and molecular role. The protein is now implicated in many biological functions including protein translation, multiple hormonal responses, developmental processes, pathogen infection resistance, environmental stress responses, and miRNA production. Such multiple functional roles are consistent with the scaffolding nature of the plant RACK1 protein. A significant advance was achieved when the β-propeller structure of the Arabidopsis RACK1A isoform was elucidated, thus revealing that its …
Welcome To The Brave New World: Crispr Mediated Genome Editing‐Pathway To Designer Babies?, Hemayet Ullah
Welcome To The Brave New World: Crispr Mediated Genome Editing‐Pathway To Designer Babies?, Hemayet Ullah
Hemayet Ullah
The world literature circle was abuzz in 1932 when Aldous Huxley published his seminal book “Brave New World”. He painted the efforts of a totalitarian state to lab manufacture “sub‐human” people who would be capable of work but not of independent thought. Though the plot was set almost 500 years in the future, the author may not have envisioned that within a century of his writing scientists would embark on developing technologies that could potentially set the road for ʺdesigner babiesʺ in the future. The recent availability of the simple, yet highly
effective, CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) …
Arabidopsis Scaffold Protein Rack1a Interacts With Diverse Environmental Stress And Photosynthesis Related Proteins, Hemayet Ullah
Arabidopsis Scaffold Protein Rack1a Interacts With Diverse Environmental Stress And Photosynthesis Related Proteins, Hemayet Ullah
Hemayet Ullah
Scaffold proteins are known to regulate important cellular processes by interacting with multiple proteins to modulate molecular responses. RACK1 (Receptor for Activated C Kinase 1) is a WD-40 type scaffold protein, conserved in eukaryotes, from Chlamydymonas to plants and humans, expresses ubiquitously and plays regulatory roles in diverse signal transduction and stress response pathways. Here we present the use of Arabidopsis RACK1A, the predominant isoform of a 3-member family, as a bait to screen a split-ubiquitin based cDNA library. In total 97 proteins from dehydration, salt stress, ribosomal and photosynthesis pathways are found to potentially interact with RACK1A. False positive …
Structure Of A Signal Transduction Regulator, Rack1, From Arabidopsis Thaliana, Hemayet Ullah
Structure Of A Signal Transduction Regulator, Rack1, From Arabidopsis Thaliana, Hemayet Ullah
Hemayet Ullah
The receptor for activated C-kinase 1 (RACK1) is a highly conserved WD40 repeat scaffold protein found in a wide range of eukaryotic species from Chlamydymonas to plants and humans. In tissues of higher mammals, RACK1 is ubiquitously expressed and has been implicated in diverse signaling pathways involving neuropathology, cellular stress, protein translation, and developmental processes. RACK1 has established itself as a scaffold protein through physical interaction with a myriad of signaling proteins ranging from kinases, phosphatases, ion channels, membrane receptors, G proteins, IP3 receptor, and with widely conserved structural proteins associated with the ribosome. In the plant Arabidopsis thaliana, RACK1A …
Rapid Signaling At The Plasma Membrane By A Nuclear Receptor For Thyroid Hormone, Hemayet Ullah
Rapid Signaling At The Plasma Membrane By A Nuclear Receptor For Thyroid Hormone, Hemayet Ullah
Hemayet Ullah
Many nuclear hormones have physiological effects that are too rapid to be explained by changes in gene expression and are often attributed to unidentified or novel G protein-coupled receptors. Thyroid hormone is essential for normal human brain development, but the molecular mechanisms responsible for its effects remain to be identified. Here, we present direct molecular evidence for potassium channel stimulation in a rat pituitary cell line (GH(4)C(1)) by a nuclear receptor for thyroid hormone, TRbeta, acting rapidly at the plasma membrane through phosphatidylinositol 3-kinase (PI3K) to slow the deactivation of KCNH2 channels already in the membrane. Signaling was disrupted by …
Rack1 Mediates Multiple Hormone Responsiveness And Developmental Processes In Arabidopsis, Hemayet Ullah
Rack1 Mediates Multiple Hormone Responsiveness And Developmental Processes In Arabidopsis, Hemayet Ullah
Hemayet Ullah
The scaffold protein RACK1 (Receptor for Activated C Kinase 1) serves as an integrative point for diverse signal transduction pathways. The Arabidopsis genome contains three RACK1 orthologues, however, little is known about their functions. It is reported here that one member
of this gene family, RACK1A, previously identified as the Arabidopsis homologue of the tobacco arcA gene, mediates hormone responses and plays a regulatory role in multiple developmental processes. RACK1A expresses ubiquitously in Arabidopsis. Loss-of-function mutations in RACK1A confer defects in multiple developmental processes including seed germination, leaf production, and flowering. rack1a mutants displayed reduced sensitivity to gibberellin and brassinosteroid …
Role Of A Heterotrimeric G Protein In Regulation Of Arabidopsis Seed Germination, Hemayet Ullah, Jin-Gui Chen, Shucai Wang, Alan M. Jones
Role Of A Heterotrimeric G Protein In Regulation Of Arabidopsis Seed Germination, Hemayet Ullah, Jin-Gui Chen, Shucai Wang, Alan M. Jones
Hemayet Ullah
Seed germination is regulated by many signals. We investigated the possible involvement of a heterotrimeric G protein complex in this signal regulation. Seeds that carry a protein null mutation in the gene encoding the alpha subunit of the G protein in Arabidopsis (GPA1) are 100-fold less responsive to gibberellic acid (GA), have increased sensitivity to high levels of Glc, and have a near-wild-type germination response to abscisic acid and ethylene, indicating that GPA1 does not directly couple these signals in germination control. Seeds ectopically expressing GPA1 are at least a million-fold more responsive to GA, yet still require GA for …
G Protein Regulation Of Ion Channels And Abscisic Acid Signaling In Arabidopsis Guard Cells, Hemayet Ullah, Xi-Qing Wang, Alan M. Jones, Sarah M. Assmann
G Protein Regulation Of Ion Channels And Abscisic Acid Signaling In Arabidopsis Guard Cells, Hemayet Ullah, Xi-Qing Wang, Alan M. Jones, Sarah M. Assmann
Hemayet Ullah
The phytohormone abscisic acid (ABA) promotes plant water conservation by decreasing the apertures of stomatal pores in the epidermis through which water loss occurs. We found that Arabidopsis thaliana plants harboring transferred DNA insertional mutations in the sole prototypical heterotrimeric GTP-binding (G) protein alpha subunit gene, GPA1, lack both ABA inhibition of guard cell inward K(+) channels and pH-independent ABA activation of anion channels. Stomatal opening in gpa1 plants is insensitive to inhibition by ABA, and the rate of water loss from gpa1 mutants is greater than that from wild-type plants. Manipulation of G protein status in guard cells may …
Abp1 Is Required For Organized Cell Elongation And Division In Arabidopsis Embryogenesis, Hemayet Ullah
Abp1 Is Required For Organized Cell Elongation And Division In Arabidopsis Embryogenesis, Hemayet Ullah
Hemayet Ullah
To directly address the function of a putative auxin receptor designated ABP1, a reverse genetic approach was taken to identify and characterize ABP1 mutant alleles in Arabidopsis. A homozygous null mutation in ABP1 confers embryo lethality. Null mutant embryos develop normally until the early stages of the globular embryo but are unable to make the transition to a bilaterally symmetrical structure because cells fail to elongate. Cell division was also aberrant both in the suspensor and embryo proper. Antisense suppression of ABP1 in tobacco cells causes slow proliferation and eliminates auxin-induced cell elongation and reduces cell division. The complete lack …