Protein Spotlight
http://www.proteinspotlight.org/spotlight/
one month, one proteinen-us2024-02-16T13:07:01+01:00fierce
http://www.proteinspotlight.org/spotlight/back_issues/266/
Scents communicate. Wrapped in silence perhaps, yet they have much to say. They may revolt us or delight us, go unnoticed or do nothing for us, but scents always have something to convey. So much so that many of us dab a little perfume on the nape of our neck or spray eau de toilette on our torso at the start of each day. We want to smell nice, or at the very least clean. We may even splash a little scent on before going out with an end to seduce. Much like flowers do. Who has not crossed a room or a lawn to inhale the wonderful perfume released by hyacinths, lilacs or a fragrant rose? Or leaned over to breathe in the delicate scent of jasmine wafting from a cup of tea? Long before humans, plants grasped the advantage of releasing pleasant volatile vibes to attract a pollinator or two. Some viruses have caught on with the practice too - and in a rather cunning way. The cucumber mosaic virus, for instance, is capable of infecting plants while also forcing them to become attractive to insects who will transfer the virus to other plants. Uncharacteristically, one sole protein in CMV can perform both actions. Its name is 2b, or CMV2b.Articlevgerrits2024-02-16T13:07:01+01:00rupture
http://www.proteinspotlight.org/spotlight/back_issues/265/
Who has not been accosted by someone they would prefer to avoid? You greet them meekly, exchange a few polite words while wondering how to cut the exchange short without being disrespectful. If being disrespectful is not an issue, however, things become gloriously easy. You could tell them that their company bores you, that you have more important things to tend to or interrupt the chat with a brisk shake of the hand and move on. If you were part of a cartoon strip, you could burst into flames or simply disintegrate. It so happens that cells can actually opt to disintegrate when dealing with something that has become toxic to their environment, or at any rate redundant. This can be a virus, a bacterium, or perhaps simply age. Such an option is generally called programmed cell death, or apoptosis. And as there are many ways of being disrespectful to your acquaintance, there are many ways a cell can choose to disappear. One is by generating fatal rips in its own plasma membrane. Though rips such as these have been observed by scientists for many years, plasma membrane rupture was long believed to be a passive event. Until a protein known as ninjurin-1 was discovered.Articlevgerrits2024-01-19T16:50:18+01:00sound and silence
http://www.proteinspotlight.org/spotlight/back_issues/264/
Like smells and tastes, sounds can whizz you back to forgotten places. The shriek of a seagull. The wash of waves. The crack of lightning. A motor's rumble. A Christmas carol. A childhood tune. More often than not, these castaway memories emerge wrapped in a delicate veil of magic. It is a wonderful feeling, of something you would like to know again but cannot, although it is there hidden deep inside you. A feeling we would be unable to remember were it not for our ears. Sound is sensed by way of vibrations that hit parts of our inner ear, an intricate part of mammalian anatomy. Here, vibrations are amplified, causing messages to be relayed to our brain that translates them into noise - which is what the act of hearing is. All sorts of proteins are involved in the perception of sound* but also in its unfortunate contrary: hearing impairment. One particular protein, connexin 26, forms intercellular channels in the cochlea of the inner ear so that molecules can transit from one cell to another. Connexin26 also happens to be involved in many forms of hearing impairment because, when dysfunctional, molecules are no longer able to pass. Articlevgerrits2023-12-22T16:10:02+01:00hot
http://www.proteinspotlight.org/spotlight/back_issues/263/
The further south and east you go, the spicier food tends to get. A spice many of us store in the kitchen cupboard are chili peppers. Fresh or dried, crushed or finely sliced and thrown into a sauce, chili peppers can set your palate on fire to varying degrees. It has to do with the amount you fling in, but also the kind of pepper you choose to chop. The substance that sparks off the well-known mixture of burn and sometimes pain is known as capsaicin - and the sensation of pain is exactly what we are supposed to feel. Chili peppers do not produce capsaicin for human pleasure and cuisine; they make it to ward off predators. No other mammal would dream of adding hot pepper to its meal! Not all peppers are pungent, however. Take bell peppers, for example. Do they produce capsaicin? No. Instead, they produce what is known as capsiate, which is not hot. Both capsaicin and capsiate are derived from the same pathways but, at the very last steps, a vanillin substrate is modified in either one of two ways. The resulting product is capsiate or capsaicin - both of which, surprisingly, are synthesized by the same enzyme, a synthase known as PUN1. Articlevgerrits2023-11-24T12:28:16+01:00self-reliant
http://www.proteinspotlight.org/spotlight/back_issues/262/
In times of perplexity, every now and then it is better to deal with things yourself. It can be a time-saver, and sometimes, too, an energy-saver. If faced, say, by an oncoming downpour, it is wiser to run for shelter rather than wait for someone to bring you an umbrella. Such decisions also exist at the cellular level. Take our immune system for instance. When attacked by a virus, our body begins by rapidly firing off a first round of artillery as it awaits further and more complex lines of defence that involve myriads of other factors. It turns out that the use of fast lanes such as these also occur at a far smaller scale. In this light, scientists recently discovered quite an extraordinary protein, known as ophMA, that belongs to the fungus Omphalotus orealius, which methylates its own C-terminal tail instead of depending on another transferase to do the job. The tail is then cleaved and folds into a cyclic peptide, an omphalotin, that has anti-nematode properties. Besides its talent for independence, ophMA also adopts a rare catenane arrangement, very similar to two rings that have been interlocked.Articlevgerrits2023-10-19T13:22:53+01:00in good time
http://www.proteinspotlight.org/spotlight/back_issues/261/
When my daughter was born, I could not help but realise that she already had inside her what would participate in giving life, if she so chose, to a daughter or a son of her own. Given a little thought, it is an extraordinary state of affairs. My daughter's ovaries were already filled to the brim with a life-time's stock of egg cells, albeit not quite mature. As it so happened, my next child was a baby boy, and I knew he would only begin to produce germ cells at puberty and cease to produce them when his life comes to an end. It is a fundamental difference between the two sexes, which obviously entails very distinct physiological makeups. Notably, on an average, egg cells must remain healthy during the best part of two decades, at the very least in these parts of the world, before one, or two, or perhaps several more are actually fertilised. Fertility is hugely dependent on egg-cell fitness, which is why many mechanisms exist to protect not only an egg's integrity but also elemental macromolecules and organelles whose activities are temporarily arrested. One protein known as ZAR1, from Zygote ARrest 1, is at the heart of such a mechanism.Articlevgerrits2023-09-18T10:51:28+01:00clearing the clamour
http://www.proteinspotlight.org/spotlight/back_issues/260/
There is an invisible and silent law that causes clutter to emerge and grow unless action is taken to deal with it. Who has not stood in the middle of a littered room and thought "Right, this needs clearing.". And for some reason, clearing clutter has this wonderful ability of also rinsing your mind. The same goes for cells. It begins at the molecular level and is called cell homeostasis, which is at the heart of any organism's health. Intracellular bodies (organelles) known as lysosomes have a major role in animal cell homeostasis, as they degrade components that are toxic to the cell, or foreign, or simply - like foodstuffs gone well beyond their sell-by dates - too old to be of any more use. When infected by bacteria, for instance, our body organises a swift initial response by calling up specialised cells known as macrophages whose role is to engulf and destroy invading pathogens. Macrophages perform this by way of their numerous lysosomes - but more importantly thanks to a protein known as TFEB that, upon infection, is activated to stimulate lysosome biosynthesis.Articlevgerrits2023-07-26T10:03:41+01:00on ants, bandicoots and Gilbertian mimicry
http://www.proteinspotlight.org/spotlight/back_issues/259/
Nature has its way of adapting to almost - if not every - known condition on Earth. It may take some time, but she gets there in the end. Adaptation has one sole aim: survival or, at the very least, a little more comfort. One of the most recent and dramatically rapid examples of biological adaptation occurred in Great Britain following the industrial revolution. Soot had begun to pollute cities which drove the peppered moth, Biston betalaria, to change its colour from speckled black to only black, making it far less conspicuous when resting against the soot-stained walls*. Many insects have devised ways to trick their predators through the art of mimicry. One ant, Myrmecia gulosa, commonly known as the giant bull ant makes use of a form of molecular mimicry: its body has not changed colour but the ant has acquired a protein that parodies a hormone which belongs to its predators, and is able to inflict lasting pain following a sting. The protein is known as OMEGA-myrmeciitoxin(02)-Mg1a, or simply Mg1a, and has recently been shown to mimic vertebrate epidermal growth factor.
Articlevgerrits2023-06-29T12:03:25+01:00a shrewd tweak
http://www.proteinspotlight.org/spotlight/back_issues/258/
The chairs were rickety. So I rummaged around the kitchen drawer, extracted an old knife and used its tip to drive a few screws back into the wood. The knife kept on losing grip and I kept on swearing. The fastest and least infuriating way to have done the job would have been to go down to the cellar and find a screwdriver. Both utensils can be used to drive in screws, but one has been intentionally manufactured to perform just that, simultaneously reducing the time and energy involved. Nature, too, has its screwdrivers. Given time and chance, it will always take the opportunity to select a commodity which will make things, if not easier, at least more in tune with what is needed. One example: ribosomes are huge molecular complexes whose role is to synthesize proteins in cells. Until recently, it was thought that all ribosomes were alike. A bit like kitchen knives. However, it turns out that some ribosomes differ slightly in their makeup and are found only in certain kinds of cell - presumably because they synthesize proteins particular to these cells. One such ribosome has been discovered in sperm cells, along with a protein known as large ribosomal subunit protein eL39-like*, or RPL39L.Articlevgerrits2023-05-24T11:14:39+01:00the slime inside us
http://www.proteinspotlight.org/spotlight/back_issues/257/
When I was small, I used to visit an elderly lady who lived next door to us. With her, I would make rice-filled frogs. The kind you can fling from one end of a room to land flat, with a plod and no bounce, onto the arm of a chair or the back of a sofa. In the 1970s, these colourful frogs haunted every household in the UK. As I painstakingly cut out frog-shaped pieces of paisley-patterned material, Lady Clarke, as she was called, used to tower over me, observing my every move with a drop always hanging off the end of her nose. I would sit there terrified that it would lose grip and drip on to me. But it never did. It just wobbled, menacingly, until it was wiped away with a handkerchief Lady Clarke kept tucked up one of her sleeves. That drop was mucus. Besides exuding from our nose, especially when we have a cold or when we get old, mucus lines the mucous membranes of our body, where it keeps things lubricated and, generally, healthy. Mucus is composed of a lot of water and several macromolecules, among them glycoproteins that carry sialic acid. Why sialic acid? Because it helps to keep pathogens away. And how does it get there? By way of sialyltransferases.Articlevgerrits2023-04-21T11:46:56+01:00in the beginning
http://www.proteinspotlight.org/spotlight/back_issues/256/
It is one of the many mysteries of our existence. How does life begin? What gives the first nudge? Is there, for that matter, a primordial poke? Over the millennia, scholars have tried to define the actual notion of life as a whole - which may seem obvious to some, but just sit down for a while and give it a thought. How are creatures made? How do they begin? What, for instance, goes on inside a womb? Theories varied according to the knowledge of the times, and explanations shifted from the near mystical to the anatomical, closely followed by the cellular until the 1980s, when - thanks to the rise of novel technologies - researchers could consider embryology at the level of the molecular. Though we are still really asking the same questions, what we know about the making of life has been dramatically fine-tuned and we now delve into the minute, wondering which molecules drive cells to become one part of an organism or another. What factors kickstart the process of a cell's fate? Today, we have part of the answer: the tetra-peptide repeat homeobox proteins. Transcription factors without which the very first embryonic cell divisions would not occur.Articlevgerrits2023-03-18T11:56:56+01:00on the end of a leash
http://www.proteinspotlight.org/spotlight/back_issues/255/
It has been a long time since I saw a plug hanging from the side of a bathtub. Remember the small triangular ring the chain dangled from, and the actual plug at the other end - usually a piece of black and slimy rubber that fitted perfectly into the plug hole. As a child, the perfection of the fit used to fascinate me and I would sit in the bath, pulling the plug out and pushing it back in again, fighting against the swirl and dynamics of flowing water. The system is straightforward enough. If you do not want the bath to empty, take something large, strong and watertight to fill the hole. You may think we are the inventors of the plug, but we are not. Filamentous fungi have been using the same kind of approach for millions of years to obstruct large holes, or septal pores, whose role is to let cytosol migrate from one part of the fungus to another. Sometimes it is necessary to seal the pores off, however. This happens thanks to organelles known as Woronin bodies which, just like the bath plug, are tethered close by.
Articlevgerrits2023-02-17T14:20:31+01:00on a tightrope
http://www.proteinspotlight.org/spotlight/back_issues/254/
Too much of anything is never good. Excess alcohol, and our faculties are impaired. Excess heat, and drought spreads. Excess cold, and vineyards die. Too much, too, of what is paradoxically essential to life frequently turns out to be toxic. Consider oxygen, iron, zinc or vitamins to name but four. Though we may be acquainted with the symptoms of what 'too much' entails, these are merely the superficial echo of cells under stress. Over the aeons, and throughout the living kingdom, organisms have had to deal with periodical over-abundances of many things. While selecting systems to use them in small doses, they promoted others to keep them in check. As an illustration, iron is vital for ferrying oxygen in organisms, and it is crucial in DNA synthesis, DNA repair and other fundamental cellular processes. Yet, too much iron will kill a cell - a process known as ferroptosis. Though this may be an ideal way of ridding a tissue of unhealthy cells, alternative processes have also evolved to stabilise things and prevent ferroptosis. One of these processes involves a protein known as ferroptosis suppressor protein 1, or FSP1.Articlevgerrits2023-01-23T15:46:43+01:00a heated legacy
http://www.proteinspotlight.org/spotlight/back_issues/253/
Stress. We know what it feels like. Though we may be the only living organism to have turned it into a fertile and imaginative piece of conversation, every single living species on this planet is prone to stress and its effects. It comes in many forms - heat, cold, hunger, overwork, noise, pressure, weight, toxicity - and gives rise to an array of symptoms such as migraine, fatigue, weariness, depression, indigestion, eczema, insomnia, and this is only an anthropocentric list! Sloths, birds, grapes or butterflies may not be accustomed to work overload or headaches but they do suffer from heat, drought or deforestation for example, as do so many species on earth. To guarantee their survival and hence reproduction, organisms have developed mechanisms to challenge stress. Some plants for example, are equipped with sensors that detect heat shock thereby setting off pathways that will not only protect the plant but also compel it to flower faster under the strain. Some plants also seem to acquire the capacity to remember heat and react faster to it when it occurs again, or even to transmit this memory to their progeny. How? Thanks to the action of at least two proteins: HSFA2 and HTT5.Articlevgerrits2022-12-22T17:38:45+01:00delayed
http://www.proteinspotlight.org/spotlight/back_issues/252/
Better safe than sorry. Leaving - whatever or whoever it may be - is always better when executed with some forethought and organisation. Cells sometimes behave similarly. Many are the occasions when our bodies decide to get rid of cells for the sake of health and equilibrium. The notion is easy to grasp when you consider cells that have either aged or been infected; our system is better off without them. Organisms have several ways of removing cells or, in other words, of programming cell death. Sometimes, though, an ongoing programme moves too fast and, rather like writing a will, the cell needs more time to arrange a few important things before its passing. So, a temporary reanimation mechanism kicks in. Enzymes known as caspases are frequently involved in programmed cell death. One particular caspase however, caspase-7, is actually engaged in repairing self-inflicted holes in a cell's membrane so that the cell has time to prepare a cleaner exit, that is to say without being detrimental to the environment.Articlevgerrits2022-11-22T13:37:42+01:00