1
|
Delgado R, Wilson CAM, Caballero L, Melo F, Bacigalupo J. Mechanical force activates the light-dependent channels TRP and TRPL in excised patches from the rhabdomere of Drosophila photoreceptors. Neuroscience 2024; 555:23-31. [PMID: 39032804 DOI: 10.1016/j.neuroscience.2024.07.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 07/04/2024] [Accepted: 07/14/2024] [Indexed: 07/23/2024]
Abstract
Drosophila phototransduction in light-sensitive microvilli involves a metabotropic signaling cascade. Photoisomerized rhodopsin couples to G-protein, activating phospholipase C, which cleaves phosphatidylinositol bisphosphate (PIP2) into inositol trisphosphate, diacylglycerol (DAG) and a proton. DAG is converted into phosphatidic acid by DAG-kinase and metabolized to L-linoleoyl glycerol (2-LG) by DAG-lipase. This complex enzyme cascade ultimately opens the light-dependent transient receptor potential channels, TRP and TRPL. PIP2, DAG, H+ and 2-LG are possible channel activators, either individually or combined, but their direct participation in channel-gating remains unresolved. Molecular interaction with the channels, modification of the channels' lipid moiety and mechanical force on the channels by changes in the membrane structure derived from light-dependent changes in lipid composition are possible gating agents. In this regard, mechanical activation was suggested, based on a rapid light-dependent contraction of the photoreceptors mediated by the phototransduction cascade. Here, we further examined this possibility by applying force to inside-out patches from the microvilli membrane by changing the pressure in the pipette or pulling the membrane with a magnet through superparamagnetic nanospheres. The channels were opened by mechanical force, while mutant lacking both channels was insensitive to mechanical stimulation. Atomic Force Microscopy showed that the stiffness of an artificial phospholipid bilayer was increased by arachidonic acid and diacylglycerol whereas elaidic acid was ineffective, mirroring their relative effects in channel activity previously observed electrophysiologically. Together, the results are consistent with the notion that light-induced changes in lipid composition alter the membrane structure, generating mechanical force on the channels leading to channel opening.
Collapse
Affiliation(s)
- Ricardo Delgado
- Department of Biology, Faculty of Sciences, University of Chile, Las Palmeras, 3425, Santiago Chile.
| | - Christian A M Wilson
- Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, University of Chile, Dr Carlos Lorca Tobar 964, Santiago Chile.
| | - Leonardo Caballero
- Department of Physics and Center for Soft Matter Research SMAT-C, Faculty of Science, University of Santiago of Chile(,)Av Libertador Bernardo O'Higgins 3363, Santiago Chile.
| | - Francisco Melo
- Department of Physics and Center for Soft Matter Research SMAT-C, Faculty of Science, University of Santiago of Chile(,)Av Libertador Bernardo O'Higgins 3363, Santiago Chile.
| | - Juan Bacigalupo
- Department of Biology, Faculty of Sciences, University of Chile, Las Palmeras, 3425, Santiago Chile.
| |
Collapse
|
2
|
Chang Y, Yang B, Zhang Y, Dong C, Liu L, Zhao X, Wang G. Identification of sex-biased and neurodevelopment genes via brain transcriptome in Ostrinia furnacalis. Front Physiol 2022; 13:953538. [PMID: 36003649 PMCID: PMC9393524 DOI: 10.3389/fphys.2022.953538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 07/01/2022] [Indexed: 11/16/2022] Open
Abstract
Insect brains play important roles in the regulation of sex-biased behaviors such as mating and oviposition. The neural structure and function of brain differences between males and females have been identified, in which the antenna lobes (AL) showed the most discrepancy, however, the whole repertoire of the genes expressed in the brains and the molecular mechanism of neural signaling and structural development are still unclear. In this study, high-throughput transcriptome analysis of male and female brains was carried on in the Asia corn borer, Ostrinia furnacalis, and a total of 39.23 Gb data and 34,092 unigenes were obtained. Among them, 276 genes displayed sex-biased expression by DEG analysis, of which 125 genes were highly expressed in the males and 151 genes were highly expressed in the females. Besides, by homology analysis against genes that have been confirmed to be related to brain neurodevelopment, a total of 24 candidate genes were identified in O. furnacalis. In addition, to further screen the core genes that may be important for sex-biased nerve signaling and neurodevelopment, protein-protein interaction networks were constructed for the sex-biased genes and neurodevelopment genes. We identified 10 (Mhc, Mlc1, Mlc2, Prm, Mf, wupA, TpnC25D, fln, l(2)efl, and Act5C), 11 (PPO2, GNBP3, Spn77Ba, Ppn, yellow-d2, PGRP-LB, PGRP-SD, PGRP-SC2, Hml, Cg25C, and vkg) and 8 (dac, wg, hh, ci, run, Lim1, Rbp9, and Bx) core hub genes that may be related to brain neural development from male-biased, female-biased, and neurodevelopment gene groups. Our results provide a reference for further analysis of the dimorphism of male and female brain structures in agricultural pests.
Collapse
Affiliation(s)
- Yajun Chang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Bin Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- *Correspondence: Guirong Wang, ; Bin Yang,
| | - Yu Zhang
- Key Laboratory of Biohazard Monitoring, Green Prevention and Control for Artificial Grassland, Ministry of Agriculture and Rural Affairs, Institute of Grassland Research of Chinese Academy of Agricultural Sciences, Hohhot, China
| | - Chenxi Dong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lei Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xincheng Zhao
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Guirong Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- *Correspondence: Guirong Wang, ; Bin Yang,
| |
Collapse
|
3
|
Critical contributions of pre-S1 shoulder and distal TRP box in DAG-activated TRPC6 channel by PIP 2 regulation. Sci Rep 2022; 12:10766. [PMID: 35750783 PMCID: PMC9232555 DOI: 10.1038/s41598-022-14766-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/13/2022] [Indexed: 11/25/2022] Open
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2 or PIP2) regulates the activities of numerous membrane proteins, including diacylglycerol(DAG)-activated TRPC3/6/7 channels. Although PIP2 binding is known to support DAG-activated TRP channel activity, its binding site remains unknown. We screened for PIP2 binding sites within TRPC6 channels through extensive mutagenesis. Using voltage-sensitive phosphatase (DrVSP), we found that Arg437 and Lys442, located in the channel’s pre-S1 domain/shoulder, are crucial for interaction with PIP2. To gain structural insights, we conducted computer protein–ligand docking simulations with the pre-S1 domain/shoulder of TRPC6 channels. Further, the functional significance of PIP2 binding to the pre-S1 shoulder was assessed for receptor-operated channel functions, cross-reactivity to DAG activation, and the kinetic model simulation. These results revealed that basic residues in the pre-S1 domain/shoulder play a central role in the regulation of PIP2-dependent gating. In addition, neutralizing mutation of K771 in the distal TRP box reversed the effect of PIP2 depletion from inhibiting to potentiating channel activity. A similar effect was seen in TRPV1 channels, which suggests that TRPC6 possesses a common but robust polarity switch mediating the PIP2-dependent effect. Overall, these mutagenesis studies reveal functional and structural insights for how basic residues and channel segments in TRP channels are controlled through phosphoinositides recognition.
Collapse
|