histidine kinase

(noun)

Histidine Kinases (HK) are multifunctional, typically transmembrane, proteins of the transferase class that play a role in signal transduction across the cellular membrane.

Related Terms

Examples of histidine kinase in the following topics:

  • Two-Component Regulatory Systems

    • Signal transduction occurs through the transfer of phosphoryl groups from adenosine triphosphate (ATP) to a specific histidine residue in the histidine kinases (HK).
    • Subsequently the histidine kinase catalyzes the transfer of the phosphate group on the phosphorylated histidine residues to an aspartic acid residue on the response regulator (RR).
    • Signal transducing histidine kinases are the key elements in two-component signal transduction systems.
    • Examples of histidine kinases are EnvZ, which plays a central role in osmoregulation, and CheA, which plays a central role in the chemotaxis system.
    • Histidine kinases usually have an N-terminal ligand-binding domain and a C-terminal kinase domain, but other domains may also be present.

  • Chemotaxis

    • The activation of the receptor by an external stimulus causes autophosphorylation in the histidine kinase, CheA, at a single highly-conserved histidine residue.
    • CheA in turn transfers phosphoryl groups to conserved aspartate residues in the response regulators CheB and CheY [note: CheA is a histidine kinase and it does not actively transfer the phosphoryl group.

  • Interferons

    • STAT activation initiates the most well-defined cell signaling pathway for all IFNs, the classical Janus kinase-STAT (JAK-STAT) signaling pathway.
    • Type I IFNs further activate p38 mitogen-activated protein kinase (MAP kinase) to induce gene transcription.
    • Antiviral and antiproliferative effects specific to type I IFNs result from p38 MAP kinase signaling.
    • The phosphatidylinositol 3-kinase (PI3K) signaling pathway is also regulated by both type I and type II IFNs.
    • PI3K activates P70-S6 Kinase 1, an enzyme that increases protein synthesis and cell proliferation; phosphorylates of ribosomal protein s6, which is involved in protein synthesis; and phosphorylates a translational repressor protein called eukaryotic translation-initiation factor 4E-binding protein 1 (EIF4EBP1) in order to deactivate it.

  • Cytomegalovirus Infections

    • Its antiviral activity requires phosphorylation by the HCMV protein kinase, pUL97.
    • HCMV drugs have been designed to target the virus' DNA polymerase (pUL54), protein kinase (pUL97), and cellular kinases.

  • Purifying Proteins by Affinity Tag

    • His-tag, 5-10 histidines bound by a nickel or cobalt chelate (HHHHHH)
    • Eighteen bases coding six histidines are inserted right after the START codon or right before the STOP codon.

  • Toll-Like Receptors

    • The adapter proteins and kinases that mediate TLR signaling have also been targeted.
    • IRAK kinases then phosphorylate and activate the protein TRAF6, which in turn polyubiquinates the protein TAK1, as well as itself in order to facilitate binding to IKKβ.
    • TRIF activates the kinases TBK1 and RIP1, which creates a branch in the signaling pathway.

  • Shuttle Vectors and Expression Vectors

    • This tag could be histidine (His) tag or any other marker peptide.

  • Diphtheria

    • This ADP-ribosylation involves the transfer of an ADP-ribose from NAD+ to a diphthamide (a modified histidine) residue within the EF-2 protein.

  • Antimicrobial Peptides

    • These peptides include two or more positively charged residues provided by arginine, lysine or, in acidic environments, histidine, and a large proportion (generally >50%) of hydrophobic residues.

  • Adherence

    • Also, they induce activation of several signal transduction cascades, including activation of PI-3 kinase.