June 25, 2018
Physiological process is the act of one cell communicating to another cell. This form of communication can be local or global. The most common form of physiological communication occurs via electrical signals known as action potentials. Ions move in and out of neurons through intermembrane proteins known as channels. The movement of ions allow for a brain cell (or neuron) to become polarized and, as a result, a signal is propagated from an affecter neuron until the target neuron is reached. Action potentials are also generated in cardiac muscle cells. Without ion channels the generation of action potentials would not be possible. Hyperpolarization-activated cyclic nucleotide-gated (HCNs) channels are found in both cardiac tissue and neurons and are central to physiological communication. The current generated by this type of channel is known as a “funny” current, this is due to the nature of the channel opening once the cell is hyperpolarized. These channels are regulated by cell polarity and second messengers such as cAMP and cGMP. In the brain, these channels have been found in regions such as the hippocampus where they are believed to play a role in neural plasticity. In cardiac tissues, these channels are involved in generating and controlling the rhythm of our hearts. HCN channels do this via a pacemaker current. Mutations affecting these channels have been associated with epilepsy and cardiac rhythm disorders. The presented image displays the beauty of this odd but important channel (PBD:5U6O)
June 18, 2018
Apoptosomes are one of several gate keepers that mediate cell death, also known as #apoptosis. In humans, apoptosomes are formed when the mitochondrial protein cytochrome c and the cytosolic protein Apaf-1 (apoptotic protease activating factor 1) bind together. Cytochrome c normally carries single electrons in the electron transport chain, but upon sensing danger it can also be released from mitochondria into the cytosol to start the intrinsic apoptosis pathway. When cytochrome c binds with harmless Apaf-1 circulating in the cell, it becomes activated as a 7-subunit complex (pictured here, PDB: 3J2T). Apoptosomes can then activate caspases that cut proteins and begin the execution of the cell. Understanding apoptosomes may help scientists cure diseases associated with premature cell death and also have greater capabilities for removing harmful cells in the body.
June 11, 2018
Luciferase is the protein ultimately responsible for the firefly's (Photinus pyralis) luminescence, which lights up the Texas sky in the early evenings. If the name sounds familiar to you, it should; both "Lucifer" and "luciferase" come from the Latin "luci feri" or "bringer of light". The protein works by breaking the bonds of a molecule called lucferin, releasing a yellow-green glow. In addition to fireflies, luciferase has also been found in symbiotic bacteria inside of squid and cuttlefish, allowing them to shine in the dark depths of our oceans. (PDB 1LCI)
June 4, 2018
Nipah Virus (NiV) has been making the news rounds recently due to an outbreak in India. 11 people have died and 25 others have been hospitalized due to this virus! According to the World Health Organization (#WHO), Nipah virus is on their list for potential viruses that can cause a global pandemic. This virus can infect both humans and animals, with the first cases of human infection caused by infected date palm sap (transmitted from fruit bats) and ingested by humans. NiV can cause major complications, such as acute respiratory syndrome and fatal encephalitis. So far, there has been no discovered vaccine for either humans or animals. Pictured is the Nipah Virus Attachment Glycoprotein (PDB ID: 2VWD). One paper published in the Journal of Virology noted that a potential cure using antibodies could be used to prevent this protein from attaching to cells (1)! How appropriate as that's exactly what we do!
May 29, 2018
Human growth hormone (HGH) , produced by the pituitary gland, spurs growth in children and adolescents. It also helps to regulate body composition, body fluids, muscle and bone growth, sugar and fat metabolism, and possibly heart function. Produced synthetically, HGH is the active ingredient in a number of prescription drugs and in other products available widely over the Internet. Some people turn to HGH with the hope that it will keep them feeling and looking youthful or help them lose weight, but experts say that these hopes are unfounded. Worse yet, these products can be harmful. PDB ID: 1HGU
May 21, 2018
Human papillomavirus (HPV) is a virus that is a common cause of cervical and oral cancer. Luckily, a vaccine for HPV is available through your physician to prevent the onset of this deadly disease. The vaccine works by inoculating the individual with “virus-like particles” composed of the L1 capsid protein (a harmless protein) that raises an immune response to protect against this virus. This image shows how antibodies coat the surface of HPV and make it unable to infect cells. PDB ID: 6bt3
May 15, 2018
Interleukin 2 (IL-2) is an important signaling molecule that is critical for a fully functional immune system. For example, IL-2 regulates the proper differentiation and maturation of certain immune cells. Fully functional IL-2 prevents the development of autoimmune disease. It is used as a cancer-fighting drug by boosting the immune system of patients. However, this drug is only useful for specific types of cancer and has very severe side effects that limit its use.
May 7, 2018
Containing over 240 distinct domains and as many as 36,000 amino acids, titin is the largest protein ever discovered. Its formal IUPAC name is the longest name for any protein, at 189,819 letters. That’s roughly equivalent to the length of 100 pages of a typical novel, and longer than any other word in any language! Titin is found primarily in striated muscle and largely consists of a series of interconnected immunoglobulin domains – the same type of domain that makes up antibodies. It is responsible for preserving and maintaining muscle elasticity, which it does with a hanging motion between domains, or, when subjected greater strain, unfolding and refolding its domains like a giant protein spring. Pictured here is a small six-domain fragment of a titin molecule - the complete protein is roughly forty times this size! PDB ID: 3B43
May 1, 2018
Pet lovers beware! You're looking at the deadly feline and canine parvoviruses. Parvovirus is a common name that refers to all viruses in the Parvoviridae family. They are known to be linear, non-segmented, and very small; having an average genome size of 5000 nucleotides. Notice how similar feline and canine parvoviruses are? That's because canine parvovirus is a mutation of feline parvovirus (the few differing residues are highlighted in green and yellow). Each virus causes disease in its namesake animal by infecting actively dividing cells. This is why puppies and kittens are at higher risk. Infection is characterized by lethargy, vomiting, loss of appetite, and diarrhea which results in life-threatening dehydration. The virus is transmitted by way of infected fluids and can survive without a host for months! Lucky for us, our little loves can be vaccinated for the disease.
April 23, 2018
Lead poisoning can occur over long stretches of time as lead builds up in the body. Major lead contamination has occurred in the water of communities like Flint, Michigan, although other sources of lead contamination include lead-based paints or lead-contaminated dust in older buildings and soil. Delta-aminolevulinic acid dehydratase is an enzyme encoded by the ALAD gene which is important for biosynthesis of a precursor to heme, important for blood homeostasis. This enzyme becomes inhibited by the presence of lead, resulting in anemia and in some cases acute porphyria.