http://www.proteinspotlight.org/spotlight/ one month, one protein en-us spotlight@sib.swiss 2026-06-30T10:07:39+01:00 hourly 1 2000-01-01T12:00+00:00 http://www.proteinspotlight.org/spotlight/back_issues/292/ Our most precious things are kept where they meet the least damage. Out of reach on a shelf, in the depths of a drawer, deposited in a bank or perhaps parked in the garage. Frequently, too, a layer of protection is added by wrapping the valuable item in cloth or placing it in a padded box. Nature does exactly the same with one of its most treasured commodities: DNA. In eukaryotes, not only is our genetic heritage tucked away in the fortress-like nucleus of cells but it is also swathed in numerous molecules to form what is known as 'chromatin'. Protecting DNA is paramount, for obvious reasons. However, to survive, cells must have access to the genes their DNA carries in order to express them. This implies that cells need to dismantle the chromatin barrier, at different locations and at any given time. It's not so much dismantling chromatin, really, as remodelling it in such a way that genes are sporadically laid bare and thus open to transcription. One of the numerous proteins involved in chromatin remodelling is ATRX, so called because it is found on the X chromosome of mammals. An intriguing fact: in marsupials, ATRX is also found on their Y chromosome. 956@http://www.proteinspotlight.org/spotlight/ Article 2026-06-30T10:07:39+01:00 http://www.proteinspotlight.org/spotlight/back_issues/291/ Sunday mornings are spent reading the news. Sometimes they're spent catching up on news. This is how, last weekend, I was sorry to learn - and so late - that the British zoologist and ethologist Desmond Morris had died. When I was young in the UK, Desmond Morris was huge. I had found his popular science books, in particular 'The Naked Ape' inspiring when I read them already twenty years after their original publication. There's a lot I wouldn't subscribe to anymore, but it was thanks to Morris that it really dawned on me that humans are animals too. We're equipped with things that have made us fundamentally different but, all in all, the way we are made follows the same guidelines as that of any animal. In the same pile of newspapers, I also read about psilocybin, the psychedelic produced by the mushroom P.semilanceata and how it seems to cause architectural changes in the brain. Still immersed in thoughts about Desmond Morris, his art immediately sprung to mind. For, yes, he was a respected surrealist artist too, and his paintings have always reminded me, in a strange sort of way, of the cellular world. The research the magic mushroom article was referring to describes a receptor psilocybin binds to in our brain, and the anatomical effects it is said to have had on several individuals. The psychedelic binds to a receptor known as 5-HT2AR, to which serotonin usually binds. 955@http://www.proteinspotlight.org/spotlight/ Article 2026-05-29T11:44:25+01:00 http://www.proteinspotlight.org/spotlight/back_issues/290/ You've arrived at the supermarket, and your trolley token is missing. It's not where you usually keep it - on your keyring, or in your bag. Flustered, you search for something to replace it. A coin of sorts. What you find, thank goodness, fits. So, you pull your trolley away from its fellow partners feeling both relieved and gratified. What you have just done is put something right that could have gone wrong. And you did it by way of an intermediate that mimicked what lacked. Situations such as these sometimes occur inside us. Enzymes may be temporarily out of order - not because something has gone wrong with them but because their substrate is lacking. As a result, they do nothing. This has been shown to happen to UXS1, an enzyme involved in forming part of our extracellular matrix which is crucial to our well-being. In the absence of an intermediate compound (UDP-4-ketoxylose), UXS1 remains inactive - which can create downstream complications. However, researchers discovered that a second enzyme, TGDS, comes to the rescue by producing an intermediate (UDP-4-keto-6-deoxyglucose) that is able to replace the one that is missing. UXS1 is thus revived and can resume its role. 954@http://www.proteinspotlight.org/spotlight/ Article 2026-04-21T13:28:27+01:00 http://www.proteinspotlight.org/spotlight/back_issues/289/ Two's company, three's a crowd. It could be a grasshopper's motto. Grasshoppers are solitary inoffensive creatures, that go about their business hopping from here to there nibbling away at grass, seed, leaves, flowers and stems. There are parts of the world, however, when meteorological conditions favour massive reproduction - such as wet weather after a period of drought, and the sudden growth of greenery - and grasshoppers will begin to aggregate, creating at the same time a fertile playground for multiplication. A grasshopper that aggregates is called a locust. There is no taxonomical difference between the two, just a shift in the grasshopper's behaviour and morphology. A band of locusts will grow into a swarm which can become a plague where billions of locusts migrate together landing on crops that they will devour, before moving onto the next. Besides rain after drought, what could prompt a solitary grasshopper to become gregarious? The answer is 4-vinylanisole, or 4VA, a pheromone that is released by locusts and seduces other locusts. 4VA becomes active - although it would be more apt to say attractive - by binding to a protein receptor on the locust's antennae. The olfactory receptor 35, or OR35. 953@http://www.proteinspotlight.org/spotlight/ Article 2026-03-20T16:40:29+01:00 http://www.proteinspotlight.org/spotlight/back_issues/288/ Take a child. Show it two toy animals that differ in height and ask which is the mum and which is the dad. The youngster will probably point to the tallest and say: "That's the dad". Because that is what we see in real life. It is also the way humans, like animals, are usually depicted in children's books and films. Remember "Goldilocks and the three bears"? The bigness of Dad, the 'mediumness' of Mum and the littleness of Baby bear? It's not only fiction, though. On an average, men are indeed taller than women. Why? Undoubtedly, natural selection will have played a role. Tall men are imposing, and hence instinctively sensed as dominant figures that can offer protection. Over the course of time, female humans will have been attracted to them for status as well as to ensure their progeny's safety and, who knows, inheritance of the trait. But this doesn't explain the underlying biology that makes a man taller than a woman. Recently, an intriguing explanation emerged. We know that the SHOX protein is involved in bone growth and elongation. What was discovered is that the protein is less expressed in women than it is in men because of the chromosomal location of its gene. 952@http://www.proteinspotlight.org/spotlight/ Article 2026-02-20T16:08:33+01:00 http://www.proteinspotlight.org/spotlight/back_issues/287/ Survival is the essence of life. This may sound like an abysmal platitude but, in the living world, the act of survival implies an awful lot. To survive, many animals eat other animals, which they must first kill. Birds swallow seeds thus depriving them of a chance to grow into plants. Fungi destroy crops as they use them for their own reproduction. So life, or survival, is also strongly associated with death. A lot is going on at the molecular level too, where myriads of pathways are set into action as a response to nutrition, to infection or to a predator's attack. Plants are intriguing in that their survival cannot depend on mobility: they are unable to flee predators or infection, and quite unfitted to run after prey. Their survival depends on how their stems and leaves develop and move to catch sunlight, for instance, as well as on their means to fight off pathogens. For this, they may even benefit from the help of another species. One example has been described between poplar trees and fungi, in particular the fungus Trichoderma asperellum. T.asperellum, like all fungi, expresses small proteins known as hydrophobins which have a role in fungal growth and defence. One of these hydrophobins, HFB2-6, can prompt poplar signalling pathways that are crucial for the tree's own growth and defence. 951@http://www.proteinspotlight.org/spotlight/ Article 2026-01-24T11:17:55+01:00 http://www.proteinspotlight.org/spotlight/back_issues/286/ As I crossed Geneva this morning and approached the office, I felt a growing sadness. I realised that, if I was walking in this direction in the first place, it was thanks to Amos Bairoch. Flashback to 1993: I have just emerged from a long and bumpy journey across the realm of academia, with a degree in biology and in dire need of a job. Over a glass of wine, my mother mentions my case to a distant aunt who gives it a thought as she serves herself to an olive. A nephew of hers might be able to help, she answers. Indeed, the nephew did. Nicolas Mermod, now a respected biologist himself, got in touch with me and said that he knew a friend who was looking for people to assist him with a database. In those days, for me at least, the word 'database' was still a hazy concept, and I wasn't sure it was my cup of tea. I was in no position to be picky, however, so I thanked my distant cousin and gave Amos a call. The following day, I found myself walking up a narrow path leading to a small house in Nyon, a town on the edge of the Lac Léman. I rang the doorbell. Though I was unaware of it at the time, it turned out to be one of these encounters that sets you on a track you least expect but, with hindsight, marks a milestone in your life. 950@http://www.proteinspotlight.org/spotlight/ Article 2025-12-18T14:53:21+01:00 http://www.proteinspotlight.org/spotlight/back_issues/285/ Water is one of the major molecules of life. Which is why the greater part of us is made of it. As a child, I found this hard to fathom. Should we not then be relatively liquid? I don't think I ever found a satisfying answer, nor did I really seek one, until I gained knowledge on the underlying physiology of organisms. Water is harboured within cells or flows in the fluids outside our cells, while our organs and tissues are held together in a semi-rigid mass thanks to our skeleton. Water is always moving around inside us too, and continuously leaves our body as we transpire, breathe or excrete - so it needs to be replaced. This is why we drink, and why we it is so important to feel the sensation of thirst. Quenching our thirst is not just deeply satisfying to our senses, it keeps us alive. But where does the sensation arise from? There's a thought. Is it just the result of a dry palate? No. The appetite for water is shaped by something far more intricate. We have a thirst centre in our brain where protein sensors measure the levels of molecules such as salt or glucose in our blood. When our organs are hungry for water, it shows in our blood and chemical messages are sent to our brain to nurture the feeling of thirst. In animals, this sensor is known as TMEM63B. 949@http://www.proteinspotlight.org/spotlight/ Article 2025-11-18T09:39:54+01:00 http://www.proteinspotlight.org/spotlight/back_issues/284/ Who hasn't gone out for some fresh air and been incommoded by the pungent smell of manure? Why have farmers been flinging dung on their ploughed fields for thousands of years? The answer is nitrogen. Though our ancestors were unaware of the chemistry involved in their actions, they did realise that what livestock excreted - urine and faeces - was good for their crops. This is because animal urine is full of urea, which is full of nitrogen. When livestock faeces and urine is mixed, the faecal enzyme urease breaks down the urea to release carbon dioxide and the nitric compound ammonia, which is volatile. That's the stench. Ammonia is fixed by plants, which then use it to form compounds as fundamental as DNA, RNA, ATP and amino acids. In animals, or humans for that matter, ammonia is actually a waste product and can be toxic at high levels. Our liver deals with this toxicity by transforming ammonia into urea. But it is not the only way to deal with this compound. Scientists discovered that the enzyme glutamine synthetase can also render ammonia harmless by transforming it into glutamine. 948@http://www.proteinspotlight.org/spotlight/ Article 2025-10-22T09:42:21+01:00 http://www.proteinspotlight.org/spotlight/back_issues/283/ My grandmother had a lovely pantry. It was a small room next to the kitchen, dedicated to the accumulation of 'non-perishables', i.e. mainly jam, rice, flour, sugar, dried potato, packets of biscuits and noodles. In some dark corner, you would invariably find a tin or two of powdered eggs or milk - a reminder of the days when fresh eggs and milk were hard to come by. My grandmother never really lost the habit of hoarding food, of storing the basics to provide sustenance to the family if needed. Cells, too, have their pantries. Germ cells, in particular. Plant germ cells have vacuoles. Birds' eggs have yolk. And mammalian oocytes have cytoplasmic lattices. All of which are used to bank nutrients for the embryonic development. Oocyte cytoplasmic lattices were discovered in the 1960s but we are only beginning to understand their molecular structure - and hence how they work. It seems, now, that cytoplasmic lattices are a place where maternal proteins accumulate to provide nutrients for developing embryos. Once thought to be composed of strings of ribosomes or keratin, we now know that cytoplasmic lattices consist of several components, one of which is a puzzling protein known as peptidyl arginine deiminase 6 or PADI6. 947@http://www.proteinspotlight.org/spotlight/ Article 2025-09-19T16:35:35+01:00 http://www.proteinspotlight.org/spotlight/back_issues/282/ There is much talk about plastic these days. And with reason. Besides depending on fossil fuels, plastic is infesting every nook and cranny of our planet because there is simply too much of it. Since the invention of bakelite in 1907, human dependency on the astonishingly varied properties of plastics has, understandably, never ceased to grow. Up popped the polyester polyethylene terephthalate, or PET, in the 1940s and an inventor's idea to use it to bottle soft drinks in the 1970s - which marked the beginning of a catastrophe. Today, we are desperate to find ways of recycling plastics and degrading them in eco-friendly ways. We have already discovered bacteria that are happy to eat PET for dinner - although not fast or efficiently enough for our liking. Lately, scientists came across a similar process that occurs in Nature when certain fungi, such as Aspergillus oryzae, invade plants. Plant cells in contact with the air are protected not only by a film of wax but also by cutin polyesters which are similar in structure to PET. Fungi have to degrade the cutin polyesters in order to reach the plants' flesh. They do this with the help of an intriguing little protein known as hydrophobin which, it turns out, can also be used to stimulate the degradation of PET. 946@http://www.proteinspotlight.org/spotlight/ Article 2025-08-26T14:42:30+01:00 http://www.proteinspotlight.org/spotlight/back_issues/281/ The nice thing about shampoo is the foam it produces. Because the soapy froth is a pleasant part of the procedure. But how many of us actually wonder why shampoo foams at all? Foaming agents is the answer. If you're using an eco-friendly shampoo, there's a chance that one of these agents is saponin, an organic chemical found in plants - notably in a plant commonly known as soapwort, soapweed, crow soap or even wild sweet William. Though native to Europe, soapwort grows naturally in many parts of the world, usually in open undisturbed places which many of us would qualify as 'overgrown': on the sides of riverbanks, on roadsides, in fields, in pastures, in rundown gardens and on abandoned home sites. It's the kind of plant we tend to ignore, although scientists are developing a keen interest in it. This is because, besides producing foam, saponins have several biological activities that could be of therapeutic interest. For this reason, a lot of effort has been put into understanding how plants synthesize saponins. It turns out that they are the end product of a metabolic pathway which involves fourteen steps and as many enzymes. 945@http://www.proteinspotlight.org/spotlight/ Article 2025-06-23T14:17:37+01:00 http://www.proteinspotlight.org/spotlight/back_issues/280/ We all begin with one cell, which divides into two - and so on. It sounds straightforward but a cell has various components (nucleus, mitochondria, Golgi apparatus...) each of which carries out vital activities. If two daughter cells are to survive, they must receive a copy of each component from the mother cell. A mother cell cannot just split in two, pour half of its contents into one cell and tilt the rest in the second. That would be like producing two cars of the same make where one is built with no engine and the other with no wheels. Every part of a cell has a specific and an essential role, which is why each part has to be inherited by progeny. Among these essential components daughter cells must receive a copy of their mother's DNA. The only way to do this is for the mother cell to double its DNA and then distribute it in such a way that the DNA in each daughter cell is identical in quantity and nature. This can occur thanks to a mechanism known as mitosis. During mitosis, a dividing cell's chromosomes (its DNA) alternate between two opposing states: individualized and clustered. It turns out that a protein - already known to scientists - is directly involved in the making of these two chromosomal states. Its name? Ki-67. 944@http://www.proteinspotlight.org/spotlight/ Article 2025-05-20T16:46:24+01:00 http://www.proteinspotlight.org/spotlight/back_issues/279/ Spermatozoa. There are no other cells in humans - or indeed in any other animals - that have the capacity to wriggle and move forward the way spermatozoa do. Blood cells may dash around our bodies but they can only do so because they are swept up in the pulse and flow of blood. Spermatozoa make progress like little animals - which is why they were called 'animalcules' by the Dutch microbiologist van Leeuwenhoek who was the first to observe them under a microscope in the 17th century. Many organisms can move like spermatozoa, such as bacteria or protists for example, but these are unicellular from the start and really only have themselves to depend upon. Spermatozoa cannot survive on their own, as they don't have the genetic makeup for that, but they can move on their own. In fact, locomotion is really all they have evolved for. Their sole aim is to reach an ovum into which they will inject their DNA. So evolution has trimmed the architecture of spermatozoa down to the very essential: a head (in which resides the nucleus) attached to a powerful tail. The tail itself is a model of biological design and technology brought about by many proteins, among which a crucial kinase known as STK33. 943@http://www.proteinspotlight.org/spotlight/ Article 2025-04-24T11:33:56+01:00 http://www.proteinspotlight.org/spotlight/back_issues/278/ Life is a powerful force. From the moment it appeared on Earth - which is estimated at roughly 4.5 billion years ago - it has never ceased to find ways of continuing, plucking from Nature what it needs to create offspring. Rich soil broken down by earthworms feeds the emerging buds of flowers. Grains shed by fruit provide hatchlings with food, and the planet's oceans stock up with plankton to sustain their schools of fish and pods of whales. This team spirit, if you like, is also found on the molecular scale. When mothers lactate, for example, their bodies draw calcium from their own bones to build the bones of their newborn. In the same vein, scientists discovered another relay at work further upstream where maternal factors are activated to replace the calcium that has been removed from the mother's bones. In this way, the mother's bones are not weakened while the baby's bones are strengthened - and life carries on. A maternal brain hormone that is directly involved in rebuilding maternal bone during lactation has recently been discovered. Its name: CCN3. CCN3 is not new to biologists, but its role in fortifying the bones of lactating mothers is. 942@http://www.proteinspotlight.org/spotlight/ Article 2025-03-25T10:51:17+01:00