Psychiatry related information on Tk

• Tachykinin-related peptides modulate odor perception and locomotor activity in Drosophila [1].

High impact information on Tk

• The cDNAs encode a seven transmembrane domain protein (DTKR) of 519 amino acids with 40-48% amino acid identity to mammalian tachykinin receptors within transmembrane regions [2].
• We identified clones encoding a Drosophila receptor for tachykinin-like peptides by low stringency screening of an embryonic cDNA library with probes from the bovine substance K receptor [2].
• Xenopus oocytes injected with DTKR cRNAs showed selective responses to vertebrate substance P, its agonists and not to other vertebrate tachykinin peptides [2].
• Analysis of the Drosophila genome allowed us to identify a putative tachykinin-related peptide prohormone (prepro-DTK) gene [3].
• The tachykinin-related peptide prohormone gene (Dtk) is both expressed and post-translationally processed in larval and adult midgut endocrine cells and in the central nervous system, with midgut expression starting at stage 17 of embryogenesis [3].

Biological context of Tk

• These are the same second messengers that are induced in mammalian neurokinin-dependent signaling processes [4].
• Multiple sequence comparisons show that the amino acid sequence of this insect receptor displays several features that are typical for tachykinin (or neurokinin, NK) receptors [5].

Anatomical context of Tk

• We have analyzed the distribution of the Dtk transcript and peptides, by in situ hybridization and immunocytochemistry during postembryonic development of the central nervous system (CNS) of Drosophila [6].
• Characterization of a receptor for insect tachykinin-like peptide agonists by functional expression in a stable Drosophila Schneider 2 cell line [4].
• Inactivation of a tachykinin-related peptide: identification of four neuropeptide-degrading enzymes in neuronal membranes of insects from four different orders [7].

Associations of Tk with chemical compounds

• Vertebrate tachykinins (or neurokinins) did not evoke any effect at concentrations up to 10(-5) M, but an antagonist of mammalian neurokinin receptors, spantide II, inhibited the Lom-TK III-induced calcium response [4].
• A few naturally occurring insect tachykinin-related peptides, such as stomoxytachykinin (Stc-TK), contain an Ala-residue instead of the highly conserved Gly-residue that is present in most other members of this peptide family [8].
• Insect tachykinin-related peptides, also referred to as "insectatachykinins", produce dose-dependent calcium and cyclic AMP responses in cultured Drosophila melanogaster Schneider 2 (S2) cells that were stably transfected with the cloned STKR cDNA [9].
• An aminoisobutyric acid-containing analogue of the cockroach tachykinin-related peptide, LemTRP-1, with potent bioactivity and resistance to an insect angiotensin-converting enzyme [10].
• The functional assay based on aequorin-derived luminescence triggered by receptor-mediated changes in Ca(2+) levels was used to examine and compare the effect of tachykinin-related peptides from different species [11].

Regulatory relationships of Tk

• DTKR was activated by all Drosophila tachykinins and inhibited by tachykinin antagonists [12].

Other interactions of Tk

• However, in comparison, the D. melanogaster tachykinins, DTK-1, DTK-2, DTK-3 and DTK-4 were poor Ance substrates [13].
• We previously reported the cloning of the neuropeptide receptor NKD, a Drosophila melanogaster homologue of the mammalian tachykinin receptors [14].
• The cDNA encodes a protein of 449 amino acids with the characteristics of a G protein-coupled receptor and shares significant amino acid identity with mammalian tachykinin receptors [15].
• Among the 38 sequenced peptides, some originate from precursors, such as the tachykinin and the IFamide precursor that were entirely missed in the first study [16].

Analytical, diagnostic and therapeutic context of Tk

• A putative tachykinin receptor in the cockroach brain: molecular cloning and analysis of expression by means of antisera to portions of the receptor protein [17].

References