Torso

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Jordi Casanova - One of the best experts on this subject based on the ideXlab platform.

  • Conserved and divergent elements in Torso RTK activation in Drosophila development
    Scientific Reports, 2012
    Co-Authors: Marco Grillo, Marc Furriols, Cristina De Miguel, Xavier Franch-marro, Jordi Casanova
    Abstract:

    The repeated use of signalling pathways is a common phenomenon but little is known about how they become co-opted in different contexts. Here we examined this issue by analysing the activation of Drosophila Torso receptor in embryogenesis and in pupariation. While its putative ligand differs in each case, we show that Torso-like, but not other proteins required for Torso activation in embryogenesis, is also required for Torso activation in pupariation. In addition, we demonstrate that distinct enhancers control Torso-like expression in both scenarios. We conclude that repeated Torso activation is linked to a duplication and differential expression of a ligand-encoding gene, the acquisition of distinct enhancers in the Torso-like promoter and the recruitment of proteins independently required for embryogenesis. A combination of these mechanisms is likely to allow the repeated activation of a single receptor in different contexts.

  • Two distinct but convergent groups of cells trigger Torso receptor tyrosine kinase activation by independently expressing Torso-like
    Proceedings of the National Academy of Sciences of the United States of America, 2007
    Co-Authors: Marc Furriols, Gemma Ventura, Jordi Casanova
    Abstract:

    Cell fate determination is often the outcome of specific interactions between adjacent cells. However, cells frequently change positions during development, and thus signaling molecules might be synthesized far from their final site of action. Here, we analyze the regulation of the Torso-like gene, which is required to trigger Torso receptor tyrosine kinase activation in the Drosophila embryo. Whereas Torso is present in the oocyte, Torso-like is expressed in the egg chamber, at the posterior follicle cells and in two separated groups of anterior cells, the border cells and the centripetal cells. We find that JAK/STAT signaling regulates Torso-like expression in the posterior follicle cells and border cells but not in the centripetal cells, where Torso-like is regulated by a different enhancer. The border and centripetal cells, which are originally apart, converge at the anterior end of the oocyte, and we find that both groups contribute to trigger Torso activation. Our results illustrate how independently acquired expression of a signaling molecule can constitute a mechanism by which distinct groups of cells act together in the activation of a signaling pathway.

  • The spatial control of Torso RTK activation: a C-terminal fragment of the Trunk protein acts as a signal for Torso receptor in the Drosophila embryo
    Development (Cambridge England), 2001
    Co-Authors: Andreu Casali, Jordi Casanova
    Abstract:

    Regulated activation of receptor tyrosine kinases depends on both the presence of the receptors at the cell surface and on the availability of their ligands. In Drosophila, the Torso tyrosine kinase receptor is distributed along the surface of the embryo but it is only activated at the poles by a diffusible extracellular ligand generated at each pole that is trapped by the receptor, thereby impeding further diffusion. Although it is known that this signal depends on the activity of several genes, such as Torso-like and trunk, it is still unclear how is generated. The identification of the signal responsible for the Torso receptor activation is an essential step towards understanding the mechanism that regulates the local restriction of Torso signalling. Here we report that a fragment containing the carboxy-terminal 108 amino acids of the trunk protein retains trunk activity and is sufficient to activate Torso signalling. We also show that this fragment bypasses the requirements for the other genes involved in the activation of the Torso receptor. These results suggest that a cleaved form of the trunk protein acts as a signal for the Torso receptor. We therefore propose that the restricted activation of the Torso receptor is defined by the spatial control of the proteolytic processing of the trunk protein.

Daryl E Klein - One of the best experts on this subject based on the ideXlab platform.

  • structural basis of neurohormone perception by the receptor tyrosine kinase Torso
    Molecular Cell, 2015
    Co-Authors: Simon Jenni, Yogesh Goyal, Marcin Von Grotthuss, Stanislav Y Shvartsman, Daryl E Klein
    Abstract:

    In insects, brain-derived Prothoracicotropic hormone (PTTH) activates the receptor tyrosine kinase (RTK) Torso to initiate metamorphosis through the release of ecdysone. We have determined the crystal structure of silkworm PTTH in complex with the ligand-binding region of Torso. Here we show that ligand-induced Torso dimerization results from the sequential and negatively cooperative formation of asymmetric heterotetramers. Mathematical modeling of receptor activation based upon our biophysical studies shows that ligand pulses are "buffered" at low receptor levels, leading to a sustained signal. By contrast, high levels of Torso develop the signal intensity and duration of a noncooperative system. We propose that this may allow Torso to coordinate widely different functions from a single ligand by tuning receptor levels. Phylogenic analysis indicates that Torso is found outside arthropods, including human parasitic roundworms. Together, our findings provide mechanistic insight into how this receptor system, with roles in embryonic and adult development, is regulated.

Norbert Perrimon - One of the best experts on this subject based on the ideXlab platform.

  • corkscrew encodes a putative protein tyrosine phosphatase that functions to transduce the terminal signal from the receptor tyrosine kinase Torso
    Cell, 1992
    Co-Authors: Lizabeth A Perkins, Inger Larsen, Norbert Perrimon
    Abstract:

    We describe the characterization of the Drosophila gene, corkscrew (csw), which is maternally required for normal determination of cell fates at the termini of the embryo. Determination of terminal cell fates is mediated by a signal transduction pathway that involves a receptor tyrosine kinase, Torso, a serine/threonine kinase, D-raf, and the transcription factors, tailless and huckebein. Double mutant and cellular analyses between csw, Torso, D-raf, and tailless indicate that csw acts downstream of Torso and in concert with D-raf to positively transduce the Torso signal via tailless, to downstream terminal genes. The csw gene encodes a putative nonreceptor protein tyrosine phosphatase covalently linked to two N-terminal SH2 domains, which is similar to the mammalian PTP1C protein.

Greg Bennett - One of the best experts on this subject based on the ideXlab platform.

  • passive stiffness of the lumbar Torso in flexion extension lateral bending and axial rotation effect of belt wearing and breath holding
    Spine, 1994
    Co-Authors: Stuart M Mcgill, John Seguin, Greg Bennett
    Abstract:

    This work investigated the passive bending properties of the intact human Torso about its three principal axes of flexion: extension, lateral bending, and axial rotation. Additionally, the effects of wearing an abdominal belt and holding the breath (full inhalation) on trunk stiffness was investigated. The Torsos of 22 males and 15 females were subjected to bending moments while "floating" in a frictionless jig with isolated Torso bending measured with a magnetic device. Belts and breath holding appear to stiffen the Torso about the lateral bending and axial rotation axes but not in flexion or extension. Torsos are stiffer in lateral bending and capable of storing greater elastic energy. Regression equations were formulated to define stiffness and energy stored for input to biomechanical models that examine low back function and for bioengineers designing hardware for stabilization and bracing or investigation of traumatic events such as automobile collision.

Paul Dizio - One of the best experts on this subject based on the ideXlab platform.

  • Kinetic analysis of arm reaching movements during voluntary and passive rotation of the Torso
    Experimental Brain Research, 2008
    Co-Authors: Simone B. Bortolami, Pascale Pigeon, Paul Dizio, James R. Lackner
    Abstract:

    Reaching movements made to targets during exposure to passive constant velocity rotation show significant endpoint errors. By contrast, reaching movements made during voluntary rotation of the Torso are accurate. In both cases, as a consequence of the simultaneous motion of the arm and the Torso, Coriolis forces are generated on the arm tending to deflect its path. Our goal in the present paper was to determine whether during voluntary Torso rotations arm movement accuracy is preserved by feed forward compensations for self-generated Coriolis forces. To test this hypothesis we analyzed and quantified the contribution of Torso rotation and translation to arm dynamics and compared the kinematics and kinetics of pointing movements during voluntary and passive Torso rotation. Coriolis torques at the shoulder increase nearly sixfold in voluntary turn and reach movements relative to reaches made without Torso rotation, yet are equally accurate. Coriolis torques during voluntary turn and reach movements are more than double those produced by reaching movements during passive body rotation at 60°/s. Nevertheless, the endpoints of the reaches made during voluntary rotation are not deviated, but those of reaches made during passive rotation are deviated in the direction of the Coriolis forces generated during the movements. We conclude that there is anticipatory pre-programmed compensation for self-generated Coriolis forces during voluntary Torso rotation contingent on intended Torso motion and arm trajectory.

  • Rapid adaptation of Torso pointing movements to perturbations of the base of support
    Experimental Brain Research, 2005
    Co-Authors: Todd E. Hudson, James R. Lackner, Paul Dizio
    Abstract:

    We investigated whether pointing movements made with the Torso would adapt to movement-contingent augmentation or attenuation of their spatial amplitude. The pointing task required subjects standing on a platform in the dark to orient the mid-sagittal plane of their Torso to the remembered locations of just extinguished platform-fixed visual targets without moving their feet. Subjects alternated pointing at two chest-high targets, 60° apart, (1) in a baseline period with the stance platform stationary, (2) during exposure to concomitant contra or ipsiversive platform rotations that grew incrementally to 50% of the velocity of Torso rotation, and (3) after return in one step to stationary platform conditions. The velocity and amplitude of Torso movements relative to space decreased 25–50% during exposure to contraversive platform rotations and increased 20–50% during ipsiversive rotations. Torso rotation kinematics relative to the platform (as well as the platform-fixed targets and feet) remained virtually constant throughout the incremental exposure period. Subjects were unaware of the altered motion of their body in space imposed by the platform and did not perceive their motor adjustments. Upon return to stationary conditions, Torso rotation movements were smaller and slower following adaptation to contraversive rotations and larger and faster after ipsiversive platform rotations. These results indicate a rapid sensory-motor recalibration to the altered relationship between spatial (inertial) Torso motion and intended Torso motion relative to the feet, and rapid re-adaptation to normal conditions. The adaptive system producing such robust Torso regulation provides a critical basis for control of arm, head, and eye movements.