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Protein spotlight

http://www.expasy.org/spotlight/

「Protein Spotlight」 (ISSN 1424-4721) は、スイスバイオインフォマティクス研究所Swiss-Protチームの月間レビューである。特定のタンパク質やタンパク質ファミリーについて、やさしく解説している。

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  • round in circles by vgerrits (2018/01/25 23:26)
    There will always be more to Nature than meets the eye. During the 1950s and the 1960s, the importance of RNA in protein synthesis gradually emerged. RNA has always been seen as a linear molecule, a bit like a sentence which has a beginning and an end, and is read from one end to the other, letter by letter, word by word. Yet in the 1970s, scientists discovered another kind of RNA molecule: one that was, to their surprise, circular. Circular RNAs were first thought to be biological oddities, something that had gone wrong in the process of transcribing a gene, and which drifted in a cell's cytoplasm the way flotsam would in the sea. But as the years went by and technology evolved, it became all too clear that there was far too much circular RNA swilling around cells for its presence to be purely accidental. Today, not only are researchers discovering that circular RNAs - or circRNAs - seem to be another way of regulating gene expression but some circRNAs can also give rise to proteins. One such circRNA is known as cir-ZNF609.
  • when the mind bends by vgerrits (2017/12/21 01:29)
    Science has its backlashes. Consider nuclear fission, or the drug thalidomide*. Psilocybin is also a discovery that brought trouble with it - though of a very different and milder kind. Psilocybin is none other than the magic referred to in "magic mushrooms". The compound was extracted from psilocybin mushrooms, and its chemical structure resolved in the late 1950s. The effects it had on the human mind were studied extensively by clinical psychiatrists in the 1960s; the intriguing results became known outside the laboratory, and readily adopted by the prevailing counterculture movements. It did take not long, however and understandably so, for magic mushrooms, like LSD, mescaline and other psychedelic drugs, to become illegal, making it very difficult for scientists to carry out research on them. Yet, they had been fast to recognise the beneficial effects psilocybin could have on patients suffering from psychiatric disorders, such as depression or schizophrenia for example. Since the turn of the millennium, and despite the administrative harassments, the interest in psilocybin has been rekindled. Recently, researchers discovered a set of four enzymes involved in the compound's synthesis: psiD, psiH, psiK and psiM.
  • whispers by vgerrits (2017/11/24 04:17)
    We all depend on cues. Without them, the notion of community would not exist. Cues are the cement of society, and their nature can be very diverse. Birds whistle. Hogs grunt. Plants give off scents. Fish use bioluminescence. Slugs release pheromones. Humans talk. Many species have more than one way of flinging cues to one another: while capable of emitting sounds, they can also discharge smells, touch each other and make gestures. Humans, for example, have brought signalling to a peak by adding clothes, tattoos, piercing, makeup, jewellery and all forms of bodily transformations to their repertoire to add refinement - and perhaps a touch of egocentricity - to their means of exchange. But though it may seem that individualism is, paradoxically, what drives communication these days, every signal is a manifestation of the belonging to a part - however small - of society. Many other animals have also evolved intricate means of communication. Ants, in particular. Over time, these insects have acquired an advanced form of social behaviour driven by these mysterious invisible cues called pheromones whose effects depend highly on a protein known as odorant receptor co-receptor, or Orco.
  • seeking past shelter by vgerrits (2017/10/26 19:29)
    Nothing can survive without the means to defend itself. If bacteria are unable to protect themselves from freezing temperatures, they perish. If we cannot fight off the flu virus, we pass away. If plants cannot ward off toxic fungi, they wilt and die. In fact, we all spend a lot of time shunning "stresses", of either biological (biotic) origin, or non-biological (abiotic) origin. The good part is that when an organism has managed to check an infection or deal with harsh conditions once, it does not forget and will react all the faster if the same thing occurs again. In other words, somehow and somewhere, memories are engraved in an organism. This is precisely how a vaccination works in humans. Needless to say, scientists have also found ways to prepare a plant's resistance mechanisms in advance by treating it with certain substances or presenting it with stressful environmental conditions. This is called plant defence priming. Researchers also observed that this acquired state of a plant can also be inherited, which is like passing down a form of instinct: that of knowing how to deal with the enemy. One protein is known to be involved in the priming process, and has no doubt a role in preserving this protective memory. It has been named protein Impaired in BABA-Induced Sterility 1, or IBS1.
  • a touch of warmth by vgerrits (2017/09/29 23:30)
    We need heat. All warm-blooded animals know this instinctively because when life leaves us, the cold creeps in fast. Heat is produced in different ways inside us, and not only to keep our body temperature at a healthy level but also to keep it stable. After the fashion of small mobile furnaces, we carry adipose tissues that are full of stored fat waiting to be burnt down to release heat - a process termed thermogenesis. Researchers are becoming more and more interested in thermogenesis, especially adaptive thermogenesis which is the capacity an organism has to adjust its energy needs according to the environment, i.e. the amount of food that is available and the surrounding climate. Because where there is talk of food, there is talk of obesity and its direct cousin diabetes, two afflictions from which millions of people currently suffer worldwide. For some time already, scientists have known that molecules known as N-acyl amino acids, are important in biological processes such as thermogenesis, but they knew little more. Until they discovered an enzyme that is secreted by fat cells in adipose tissues, which knows how to make them: peptidase M20 domain containing 1, or PM20D1.
  • a taste of light by vgerrits (2017/09/01 01:25)
    Light gave life a chance to be. Without it, our planet would not be inhabited by so many living beings of all shapes and sizes. Over time, animals, plants and all sorts of microorganisms have emerged and evolved using this source of photons in different ways. Like hosts of other creatures, we use light for vision so that we can discern individual entities that make up our environment, as well as movement within it. Bereft of that faculty, it becomes difficult to hunt prey, shun predators and attract a mate - life's basic needs for all species. Not all species have eyes though, so have devised different ways of coping with these needs. But they still use light for other purposes such as the vital metabolic pathway known as photosynthesis in plants, circadian rhythms or metabolism changes in bacteria for instance. Light can also stimulate movement, as is the case for the very small worm known as Caenorhabditis elegans. However, for all this to happen, there has to be a system in each of these organisms that can catch light and transform it to meet their requirements. This is done by way of photoreceptor proteins. And C.elegans uses one of a very special kind which is known as high-energy light unresponsive 1, or Lite-I.
  • becoming one by vgerrits (2017/07/18 23:16)
    There are different ways of producing progeny. In eukaryotes, the most widespread method is for two reproductive cells of the opposite sex to meet and fuse. This may sound straightforward but mating is never an easy affair. Not only must the two cells belong to the same species but they must also make sure that they belong to different mating-types. They then have to know how to recognise each other, adhere to one another, fuse and create a space in which their nuclei will meet, mingle and ultimately give birth to a new individual - a series of events that demonstrates how accidental any form of life is in the first place. Though to date very little is known about reproductive cell fusion on the molecular level, each of these steps probably involves a complex interplay of many different proteins. In the green alga Chlamydomonas reinhardtii scientists have unveiled part of the molecular mechanics of a protein that has a direct role in fusing such cells. It has been called Hapless 2.
  • seeing through the murk by vgerrits (2017/06/20 22:48)
    We need light to see. There are times, though, when things are so gloomy it is difficult for light to shine through. So, to beat the darkness, either we create our own light or adapt to the lack of it. In Nature, the natural habitat of many vertebrates is water - sea water or fresh water. Unlike sea water, lakes or streams can be very turbid and, thus, less easy to move around in. Over a century ago, scientists had already observed that the eyes of freshwater fish have a visual pigment system that is not the same as those of marine fish or, for that matter, land animals. Freshwater fish, for instance, are able to navigate through hazy waters the way a bird would fly across a cloudless sky. This is because they can perceive wavelengths of light that humans, for instance, cannot. For us, everything would remain blurry. More surprising, perhaps, are certain vertebrates such as bullfrogs and salmon that have both visual pigment systems, and switch from one to the other depending on the environment. How can they do this? Thanks to an enzyme, known as cytochrome P450 27C1.
  • sweet poison by vgerrits (2017/05/25 01:02)
    Where there is a will, there is a way. We have all faced situations that seem hopeless yet, given time and determination, we end up finding a solution. Nature tackles apparent dead ends by using the forces that drive evolution. In this way, features that could appear to be disabling - when considering predation, reproduction or self-defence for instance - are lifted by using well-chosen tactics. Take a lack of mobility, for example. Flowers cannot fly so, to reproduce, they entice insects with intricate scents, nectar and colours who unsuspectingly collect pollen in the process. Marine cone snails are able to move but, like all snails, are sluggish. Unable to pounce on their prey, they release a cloud of toxin - known as the nirvana cabal - that stuns their victim thus giving the snail time to catch it. Toxins that make up the nirvana cabal are of great interest to pharmacologists because they are diverse, rapid and specific. Recently, a form of insulin - Con-Ins G1 - was discovered in certain cone snails that use it to immobilize their prey by causing an insulin shock.
  • between you and me by vgerrits (2017/04/27 23:23)
    Communication has a purpose and is usually selfish. Humans have raised it to the level of entertainment in the form of books, exhibitions, politics and plays, and to while away time over smoked salmon and a glass of wine. More often than not, however, organisms communicate for survival reasons - flowers let off scent to attract pollinisers, birds whistle to seduce partners, wolves howl to gather for a hunt, ants sting to ward off predators. Reproduction and food are at the heart of communication, and have moulded it into many shapes in Nature. Messages are exchanged using noises, colours, smells and thorns, for instance, but there are other ways of passing on information that are less obvious. Pheromones are an example. Recently, scientists discovered that a certain type of virus is able to tell its progeny when to infect a host or not, depending on the concentration of a protein that has been dubbed arbitrium peptide.