In a paper published in The Plant Cell, University of Missouri scientists report for the first time the elusive role a critical protein plays in this molecular signaling pathway that regulates phototropism in plants.
Directional light that induces phototropism is sensed by a plant through the action of two light-sensing proteins, phototropin 1 and phototropin 2. These proteins act as photoreceptors and initiate the phototropic signaling response in conjunction with a third protein, called NPH3.
"If the phototropic signaling pathway were like a baseball game, the phototropins would be the pitcher and NPH3 the catcher who work together to coordinate the signal, or pitch," says Mannie Liscum, a professor of biological sciences in the College of Arts and Science and in the Christopher S. Bond Life Sciences Center. "Prior to this study, no one knew how NPH3 and the phototropins cooperated to facilitate the signal."
Using a combination of genetic and biochemical methods, Liscum and colleagues found that NPH3 functions as part of a protein complex that modifies phototropin 1 by the addition of a small protein "tag" called ubiquitin. Either a single ubiquitin or a chain of ubiquitin proteins is added, depending on the amount of light the plant "sees."
If we continue the baseball analogy, ubiquitin is the hand signals NPH3 uses to coordinate with phototropin 1 the type and sequence of signals depending on the particular lighting situation.
"In low-light conditions, phototropin 1 is modified with single ubiquitin proteins and then apparently moves to a different part of the cell. In high-light conditions, phototropin 1 is modified with multiple ubiquitin proteins and is degraded by the cell to shut down further signaling," says Liscum.
The finding may have applicability to research beyond phototropism in plants.
"The tagging of proteins with ubiquitin represents a common biochemical event throughout the biological world. In fact, many human disease pathologies are associated with alterations in ubiquitin-tagging," says Liscum. "Our studies identifying a single enzyme complex that is capable of modifying a substrate in different ways simply based on the environmental conditions may therefore have implications on fields far askew from agriculture."
The paper's co-authors include Diana Roberts and Ullas Pedmale, who are equal contributing co-first authors, as well as Johanna Morrow, Shrikesh Sachdev, and Mark Hannink, all from the University of Missouri; Esther Lechner and Pascal Genschik from the Institut de Biologie Moleculaire des Plantes du CNRS, France; and Xiaobo Tang and Ning Zheng from the University of Washington, Seattle. The research was supported by funding from the National Science Foundation and the National Institutes of Health.
Melody Kroll | EurekAlert!
Water forms 'spine of hydration' around DNA, group finds
26.05.2017 | Cornell University
How herpesviruses win the footrace against the immune system
26.05.2017 | Helmholtz-Zentrum für Infektionsforschung
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy