1. Introduction: What is the human proteome?
In 2009, students at the University of Pittsburgh published a paper that brought about a wave of publicity, claiming they could map the human proteome with a single-cell resolution. This would be quite a feat as it takes billions of cells to make up all the proteins in every compartment of your body. The National Science Foundation and the US Department of Defense funded the study.
The results have now been published and are very interesting. The authors found that modern humans can assemble only about 100 trillion or so proteins, which is about 12% of the number of proteins in all cell types of all living organisms on Earth.
It is worth saying that this exists not to state that humans cannot produce more proteins. Some human genes (e.g., human telomerase) have been discovered to be responsible for making extra copies of their genes. Additionally, these genes are activated during the aging process. They may be responsible for diseases such as cancer and diabetes mellitus — another area where humans produce more protein than any other species on Earth!
As researchers continue to discover more details about our proteomes, we will find out how much we know about how each one works, what it does and why it does it; what roles it plays within our bodies; how old we are, and why; whether we age or not; whether humans are more predisposed to certain diseases or not; etc. The study has also revealed several interesting facts:
2. What are the functions of the human proteome?
The human proteome is a collection of proteins that make up our bodies. In the past decade, students have begun to understand the functions of each one and how these proteins work to maintain the health and power of the body. After all, if we don’t keep the body running smoothly, it will eventually collapse into a deadly quagmire.
The human proteome comprises hundreds of proteins that make up almost everything that makes us human: genes, hormones, antibodies, signaling molecules, and even viruses. Apiece protein has a distinct role in our bodies: some are involved in cell division and proliferation; others are vital for movement and maintaining balance; there are even ones involved in memory formation. And they all play a critical function in staying healthy.
Moreover, every protein has a unique sequence that determines how it interacts with other proteins within the body — these interactions are called secondary or accessory functions. For example, synonyms for “helper” or “carrier” are “activator” or “coactivator”; for “effector” or “enzyme-activating molecule” is “stimulating molecule.” Each protein carries out several tasks independent of its primary function. So instead of just being an enzyme that does something specific for us (like insulin), it also becomes an activator that performs several tasks, such as making signals to cells (like neurotransmitters).
3. How is the human proteome studied?
Like multiple other parts of the human body, the human proteome is a collection of many different types of molecules. These molecules play a role in health, disease, and aging. There are multiple ways in which we can study the proteome to gain a better understanding of what is happening in it. One compelling method to do this is by looking at the patterns in proteins and proteins encoded in our genes.
This has been done by using sequencing techniques and analysis tools such as antibodies, ELISA assays, sequencing, and so on (for an in-depth discussion, see: http://www.genome-project.org/html/en/research-statistics/publications/human_proteome)the exciting thing that has been done with this type of analysis is looking at their effect on populations at risk for diseases such as cancer, diabetes, or HIV infection.
Although many different methods are used to analyze the proteomes (see: http://www.genome-project.org/), two papers have been published recently in Nature Methods which have provided valuable information about how people with specific genetic variants might be more sensitive to certain types of stressors.
4. What are the advantages of studying the human proteome?
The human proteome is a collection of the proteins your body makes, the unique sequences of genes that make up your DNA, and the physical characteristics of your cells. These three elements comprise what scientists refer to as “The Human Genome Project.”
This knowledge is invaluable in our attempts to envision the future using genetic engineering.
It can also help us understand how diseases develop and how we respond to them. For example, studies of different strains of mice have shown that genetic engineering can be used to identify predisposition genes for various diseases.
These disease-causing genes are then used in breeding programs to be more likely to be selected over time by natural selection.
Another example is HIV (human immunodeficiency virus), which causes AIDS and other human diseases. It was discovered through research with mice that repeated exposure to a particular strain could make them vulnerable to developing HIV later on in life. This discovery helped researchers develop strategies for preventing HIV infection in people with AIDS and treating people who have HIV infection before it becomes too severe or spreads completely throughout their bodies (the latter is known as an AIDS-free generation).
5. What are the challenges of studying the human proteome?
Trying to identify genes that are distinctively expressed can be challenging. In this post, I’ll share some of my experiences as a geneticist trying to make sense of the human proteome. There are many different types of genes, and every kind of gene is associated with a specific biological process. For example, the gene encoding amino acids can be related to protein synthesis, and the gene encoding enzymes can be associated with protein catabolism. Each pathway is also specific to a particular cell type and tissue.
Human proteins express differently in two main ways: intracellular translation and extracellular secretion (often in different directions). Intracellular expression refers to proteins produced by the cell when it needs them, whereas extracellular proteins are secreted from the cell when it no longer needs them. Intracellularly expressed proteins include those encoded by nuclear genes such as those found in ribosomes and those encoded by mitochondrial genes such as those found in mitochondria.
Extracellularly expressed proteins include those encoded by cytoplasmic genes such as those found in ribosomes or organelles like mitochondria or peroxisomes (which we mentioned earlier).
The vast majority of intracellularly expressed proteins have no known function outside the cell; they are made at higher levels than their counterparts without having any demonstrable effect on anything outside of the cell that makes them.
Some intracellularly expressed proteins might play essential roles in cellular processes like metabolism and signal transduction when we aren’t aware of them. Still, we don’t know what they do for sure because we don’t have any laboratory evidence for their existence.
Some extracellularly-expressed proteins might have functions like transmitting signals between neurons or regulating the response to external stimuli, but these hypotheses haven’t been tested yet.
Once we understand what intracellularly-expressed molecules do, it will become easier to start determining which ones are important enough to list on our genome databases (which would allow us to use existing tools like RNA sequencing or antibody arrays). However, there aren’t enough studies investigating how specific genes are expressed across tissue types, so this area is still pretty much unexplored.
6. Conclusion: The importance of the human proteome
Recently, the human proteome has become a popular topic in the scientific community. The human proteome is the body’s proteome. Our genetic makeup, microbiome, and what makes us who we are.
The human proteome is a highly complex substrate with more than 3 million proteins in each of our cells. Paired with other complex molecules such as receptors and phosphatases, the proteins within our bodies make up the brain. This discovery has led to a vast array of questions surrounding how we can interact with each other and how genes, in particular, affect behaviors, health, and disease processes. It has spread up an entirely new field of research known as “cellular genomics,” which has rapidly grown into an annual event at conferences worldwide.
As one of these events is ending, it becomes time to look at the human proteome and if there is anything that science can teach us about ourselves.