For more than a century, neuroscience has been built around a neuron-centered worldview. The heroes of this story are familiar neurotransmitters: dopamine, serotonin, norepinephrine, acetylcholine, glutamate, and GABA. Textbooks describe neurons communicating across synapses in brain circuits using these specialized chemical messengers. The vast ‘connectome’ network of axons and dendrites was believed to determine mental events. Neurons were viewed as the only true informatio

For more than a century, biology has largely viewed cellular communication as a chemical process. This chemical view has been very helpful in describing a large number of cellular signaling pathways. However, modern cell biology increasingly reveals a deeper reality. Cells are not simply bags of chemicals. They are highly organized information-processing systems operating across many scales simultaneously. Within every cell, billions of molecules continuously exchange infor

When most people imagine a living cell, they picture a microscopic bag of organic materials. In fact, as described in prior posts, a cell is a vast, organized society whose members constantly communicate, cooperate, negotiate, compete, and adapt to changing conditions. At the center of this society lies a remarkable transportation system: an immense network of molecular tracks, scaffolds, motors, signaling complexes, organelles, and regulatory molecules that continuously exch

Dynein is a vastly more complex motor than kinesin. It walks along microtubules carrying vesicles, RNA granules, mitochondria, signaling complexes, and even large full chromosomes. It moves the entire cell nucleus during immune cell movement and manages the extraordinarily complex choreography of chromosome separation during cell division. It is a motor with awareness of what each situation requires. Dynein is enormous. Including its essential additional dynactin complex, i

Kinesin is an individual cellular motor made of just four protein chains that senses, navigates, makes decisions, and walks with two feet, step by step like a human. It picks up a variety of cargo, such as vesicles, mitochondria, molecular complexes, or messenger RNA and walks, one deliberate step at a time, along a highway of protein cables toward a precise destination. Walking upright on two legs is rare in nature—humans, ostriches, penguins, kangaroos, and a few others—e

Many of the cell’s most important functions occur through the actions of a huge, dynamic, complex scaffold that extends throughout the cell. It consists of tracks along which molecular motors walk and carry necessary cargo everywhere in the cell. This scaffold is not made like rigid, passive railroad tracks, but tracks that grow, shrink, and bend—precisely organized, but dynamic and instantly responsive. The tracks stretch from the cell's center outward like spokes, providing

Since DNA’s discovery, molecular biology had operated on reassuring assumptions: every protein folds into one precise, stable shape; shape determines its function; and shape is determined by a sequence of amino acids produced by a sequence of DNA letters. It was a clean idea. The holy grail of bioscience for decades was finding the shapes of proteins and the DNA codes that determine that shape. It is very difficult to determine the shapes of any protein from the sequence of a

Water is the medium that makes life possible. Water is so ordinary that we rarely think of it as doing anything. But inside a living cell, water is not a passive background—it is an active participant in nearly every molecular event and every cellular structure. The water molecule has a peculiar geometry. One oxygen atom pulls so strongly on two hydrogen atoms that it ends up slightly negative, while the two hydrogens are left slightly positive, which results in four partial

Most people picture molecules as rigid, locked-together structures — like tiny pieces of stone. But the molecules inside every living cell are something far more remarkable: they hold together loosely and temporarily on purpose. The strongest molecular bonds—called covalent bonds—share electrons so firmly that breaking them requires a serious chemical event. These strong bonds produce the stable structures of large molecules like DNA, RNA, lipids, and proteins. When the DNA/R

Alternative splicing of messenger RNA has been shown to be critical for the development of the human brain. The ability to make many new and complex proteins allowed the development of the enormous molecular complexity in different neurons and in different regions. For some reason, in evolution humans developed the ability to use alternative splicing much more than other species. This ability is most prominent in the brain. This post updates the most recent understanding of h

Some think viruses are not alive. It is, therefore, very surprising that they can evade elaborate cellular mechanisms used to find and destroy them. Search and destroy mechanisms of the cell and counter attacks from viruses are very complex. Cells use many sensors to find DNA and RNA that is not where it is supposed to be. When found, other mechanisms are triggered to get rid of it. Major cellular tools are pattern recognition receptors with enormous numbers of variations all

Only a very small percentage of the world’s microbes have been discovered, and even less of the much more plentiful and diverse viruses. So, it is not surprising that many dramatic new viruses have recently been found that alter our understanding of evolution. The giant Pandora viruses and many new unique ocean phages have brought forth questions about the validity of the current three-limbed diagram of the tree of life (archaea, bacteria, eukarya). With viruses and virus lik

50% of the human genome consists of jumping genes or mobile genetic elements. The 8% of human DNA from retroviruses has been vital to human evolution, such as determining the human placenta, epigenetic changes in the brain and digestive enzymes. An epigenetic immune system in the nucleus battles the jumping genes for control of the cell and control of evolution. Jumping genes, being large strands of DNA with specific functions, are much more likely to be the drivers of evol

The regulation of DNA is fantastically complex with many different layers: changing 3D shapes of the chromatin and loops of DNA; regional differences in nuclear DNA; large numbers of different epigenetic tags on DNA nucleotides and protective protein histone molecules; complex DNA repair mechanisms and alternative messenger RNA splicing; hundreds of thousands of transcription factors; and many different kinds of small and large RNAs that influence every aspect of the process.

A previous post noted how microbes can help cancers in all stages of their development. Now, it has been found that the one-time microbe now the mitochondria is also vital for cancer to start, to grow, to survive and to metastasize. These microbes and the mitochondria use back and forth communication to help cancers in many ways. This post describes the recent research about mitochondria and its vital relationship to cancer. Mitochondria Joined Forces With Our Cells Two billi

Communication among cells is the basis of all immune and nervous system activity. Research continues to find large vocabularies of signals in different languages—neurotransmitters, cytokines, small RNAs, protein transcription factors, small lipid molecules and glycan sugars. The numbers of signals is growing fantastically with at least 50 neurotransmitters, 100 cytokines, thousands of transcription factors and small RNAs and as yet indefinable large number of ubiquitin tags,

The largest number of brain molecules are lipids (fats). Unique regulation of brain lipids is complex and contributes to many diseases. Surprisingly, it has been found that membrane lipids direct proteins and proteins direct lipids. Previous posts have discussed the importance of lipids in communication between brain cells using vesicles made with fatty membranes. The rapid complex process where lipid covered vesicles transmit neuro transmitters at synapses uses 80% of all o

Living among trillions of microbes, it is necessary to determine which are going to cause disease. This is done by recognizing patterns with special receptors on immune cells—pattern recognition receptors or PPRs. Once triggered, receptors activate powerful mechanisms to cause inflammation that is life saving but, also, can attack our own cells with chronic inflammation and autoimmune diseases. In fact, as with every other critical aspect of physiology, pattern recognition re

How can one protein molecule function as if it is a brain? It is able to monitor a large amount of different external and internal information and use this data to make critical decisions and take many simultaneous actions. The decisions involve multiple pathways controlling cellular growth and the amount of protein manufacturing; actions include triggering specific genetic networks for many different tasks including balancing of basic metabolism and energy production. It is

A view of DNA from 2014 which continues to unexplained by modern scientific theories.