scholarly journals Characterization of CHARK, an unusual cytokinin receptor of rice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mhyeddeen Halawa ◽  
Anne Cortleven ◽  
Thomas Schmülling ◽  
Alexander Heyl
Keyword(s):  
Bioinformatic Analysis ◽  
Kinase Domain ◽  
Binding Domain ◽  
Cytokinin Signaling ◽  
Serine Threonine Kinase ◽  
Cytokinin Receptor ◽  
Growth Defects ◽  
Cytokinin Receptors ◽  
Bona Fide

AbstractThe signal transduction of the plant hormone cytokinin is mediated by a His-to-Asp phosphorelay. The canonical cytokinin receptor consists of an extra cytoplasmic hormone binding domain named cyclase/histidine kinase associated sensory extracellular (CHASE) and cytoplasmic histidine kinase and receiver domains. In addition to classical cytokinin receptors, a different type receptor—named CHASE domain receptor serine/threonine kinase (CHARK)—is also present in rice. It contains the same ligand binding domain as other cytokinin receptors but has a predicted Ser/Thr—instead of a His-kinase domain. Bioinformatic analysis indicates that CHARK is a retrogene and a product of trans-splicing. Here, we analyzed whether CHARK can function as a bona fide cytokinin receptor. A biochemical assay demonstrated its ability to bind cytokinin. Transient expression of CHARK in protoplasts increased their response to cytokinin. Expression of CHARK in an Arabidopsis receptor double mutant complemented its growth defects and restored the ability to activate cytokinin response genes, clearly demonstrating that CHARK functions as a cytokinin receptor. We propose that the CHARK gene presents an evolutionary novelty in the cytokinin signaling system.

scholarly journals A Novel Transmembrane Ser/Thr Kinase Complexes with Protein Phosphatase-1 and Inhibitor-2

2002 ◽  
Vol 277 (51) ◽  
pp. 49605-49612 ◽  
Author(s):  
Hong Wang ◽  
David L. Brautigan
Keyword(s):  
Protein Phosphatase ◽  
Transmembrane Protein ◽  
Kinase Domain ◽  
Protein Phosphatase 1 ◽  
Transmembrane Helices ◽  
Serine Threonine Kinase ◽  
Cellular Processes ◽  
Terminal Domain ◽  
Regulatory Complex

Protein kinases and protein phosphatases exert coordinated control over many essential cellular processes. Here, we describe the cloning and characterization of a novel human transmembrane protein KPI-2 (Kinase/Phosphatase/Inhibitor-2) that was identified by yeast two-hybrid using protein phosphatase inhibitor-2 (Inh2) as bait. KPI-2 mRNA was predominantly expressed in skeletal muscle. KPI-2 is a 1503-residue protein with two predicted transmembrane helices at the N terminus, a kinase domain, followed by a C-terminal domain. The transmembrane helices were sufficient for targeting proteins to the membrane. KPI-2 kinase domain has about 60% identity with its closest relative, a tyrosine kinase. However, it only exhibited serine/threonine kinase activity in autophosphorylation reactions or with added substrates. KPI-2 kinase domain phosphorylated protein phosphatase-1 (PP1C) at Thr320, which attenuated PP1C activity. KPI-2 C-terminal domain directly associated with PP1C, and this required aVTFmotif. Inh2 associated with KPI-2 C-terminal domain with and without PP1C. Thus, KPI-2 is a kinase with sites to associate with PP1C and Inh2 to form a regulatory complex that is localized to membranes.

scholarly journals Identification and Characterization of the CDK12/Cyclin L1 Complex Involved in Alternative Splicing Regulation

2006 ◽  
Vol 26 (7) ◽  
pp. 2736-2745 ◽  
Author(s):  
Hung-Hsi Chen ◽  
Yu-Chiuan Wang ◽  
Ming-Ji Fann
Keyword(s):  
Alternative Splicing ◽  
Rna Processing ◽  
Kinase Domain ◽  
Splicing Factors ◽  
Cyclin Dependent Kinase ◽  
Small Interfering Rnas ◽  
Sr Protein ◽  
Splicing Pattern ◽  
Bona Fide

ABSTRACT CrkRS is a Cdc2-related protein kinase that contains an arginine- and serine-rich (SR) domain, a characteristic of the SR protein family of splicing factors, and is proposed to be involved in RNA processing. However, whether it acts together with a cyclin and at which steps it may function to regulate RNA processing are not clear. Here, we report that CrkRS interacts with cyclin L1 and cyclin L2, and thus rename it as the long form of cyclin-dependent kinase 12 (CDK12L). A shorter isoform of CDK12, CDK12S, that differs from CDK12L only at the carboxyl end, was also identified. Both isoforms associate with cyclin L1 through interactions mediated by the kinase domain and the cyclin domain, suggesting a bona fide CDK/cyclin partnership. Furthermore, CDK12 isoforms alter the splicing pattern of an E1a minigene, and the effect is potentiated by the cyclin domain of cyclin L1. When expression of CDK12 isoforms is perturbed by small interfering RNAs, a reversal of the splicing choices is observed. The activity of CDK12 on splicing is counteracted by SF2/ASF and SC35, but not by SRp40, SRp55, and SRp75. Together, our findings indicate that CDK12 and cyclin L1/L2 are cyclin-dependent kinase and cyclin partners and regulate alternative splicing.

Molecular Characterization of Rotavirus Porcine OSU Carbohydrate- Binding Domain VP8*

2015 ◽  
Vol 12 (1) ◽  
pp. 69-72
Author(s):  
Hao Li ◽  
Wei Zhang ◽  
Hong-hao Zhou ◽  
Xiao-li Li
Keyword(s):  
Molecular Characterization ◽  
Binding Domain ◽  
Carbohydrate Binding

scholarly journals SEL-5, A Serine/Threonine Kinase That Facilitates lin-12 Activity in Caenorhabditis elegans

Genetics ◽  
1999 ◽  
Vol 153 (4) ◽  
pp. 1641-1654 ◽  
Author(s):  
Hanna Fares ◽  
Iva Greenwald
Keyword(s):  
Cell Fate ◽  
Point Mutations ◽  
Kinase Domain ◽  
Terminal Region ◽  
Serine Threonine Kinase ◽  
Intracellular Domain ◽  
Cell Fate Decisions ◽  
Threonine Kinase ◽  
Amino Terminal ◽  
Fate Decision

Abstract Ligands present on neighboring cells activate receptors of the LIN-12/Notch family by inducing a proteolytic cleavage event that releases the intracellular domain. Mutations that appear to eliminate sel-5 activity are able to suppress constitutive activity of lin-12(d) mutations that are point mutations in the extracellular domain of LIN-12, but cannot suppress lin-12(intra), the untethered intracellular domain. These results suggest that sel-5 acts prior to or during ligand-dependent release of the intracellular domain. In addition, sel-5 suppression of lin-12(d) mutations is tissue specific: loss of sel-5 activity can suppress defects in the anchor cell/ventral uterine precursor cell fate decision and a sex myoblast/coelomocyte decision, but cannot suppress defects in two different ventral hypodermal cell fate decisions in hermaphrodites and males. sel-5 encodes at least two proteins, from alternatively spliced mRNAs, that share an amino-terminal region and differ in the carboxy-terminal region. The amino-terminal region contains the hallmarks of a serine/threonine kinase domain, which is most similar to mammalian GAK1 and yeast Pak1p.

scholarly journals Characterization of an RNA-binding domain in the bacteriophage phi 29 connector.

1993 ◽  
Vol 268 (27) ◽  
pp. 20198-20204
Author(s):  
L.E. Donate ◽  
J.M. Valpuesta ◽  
C Mier ◽  
F Rojo ◽  
J.L. Carrascosa
Keyword(s):  
Rna Binding ◽  
Binding Domain ◽  
Rna Binding Domain

Expression, purification and characterization of the RhoA-binding domain of human SHIP2 in E.coli

2021 ◽  
pp. 105821
Author(s):  
Heng Zhou ◽  
Xiali Yue ◽  
Zi Wang ◽  
Shuangli Li ◽  
Jiang Zhu ◽  
...  
Keyword(s):  
Binding Domain ◽  
Purification And Characterization
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