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Phospholamban
Phospholamban, also known as PLN or PLB, is a micropeptide protein that in humans is encoded by the ''PLN'' gene. Phospholamban is a 52-amino acid integral membrane protein that regulates the calcium (Ca2+) pump in cardiac muscle cells. Function This protein is found as a pentamer and is a major substrate for the cAMP-dependent protein kinase ( PKA) in cardiac muscle. In the unphosphorylated state, phospholamban is an inhibitor of cardiac muscle sarcoplasmic reticulum Ca2+-ATPase ( SERCA2) which transports calcium from cytosol into the sarcoplasmic reticulum. When phosphorylated (by PKA) - disinhibition of Ca2+-ATPase of SR leads to faster Ca2+ uptake into the sarcoplasmic reticulum, thereby contributing to the lusitropic response elicited in heart by beta-agonists. The protein is a key regulator of cardiac diastolic function. Mutations in this gene are a cause of inherited human dilated cardiomyopathy with refractory congestive heart failure. When phospholamban is phosp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ATP2A1
Sarcoplasmic/endoplasmic reticulum calcium ATPase 1 (SERCA1) is an enzyme that in humans is encoded by the ''ATP2A1'' gene. Function This gene encodes one of the SERCA Ca2+-ATPases, which are intracellular pumps located in the sarcoplasmic or endoplasmic reticula of muscle cells. This enzyme catalyzes the hydrolysis of ATP coupled with the translocation of calcium from the cytosol to the sarcoplasmic reticulum lumen, and is involved in muscular excitation and contraction. Clinical significance Mutations in this gene cause some autosomal recessive forms of Brody disease, characterized by increasing impairment of muscular relaxation during exercise. Alternative splicing results in two transcript variants encoding different isoforms. Alternative splicing of ATP2A1 is also implicated in myotonic dystrophy type 1. ATP2A1 SERCA pumps were very strongly down regulated in amyotrophic lateral sclerosis. Interactions ATP2A1 has been shown to interact Advocates for Informed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arnold Martin Katz
Arnold Martin Katz (July 30, 1932 – January 25, 2016) was a medical doctor, professor of cardiology, medical researcher, and author of medical textbooks and research articles. Career Arnold Katz was born in Chicago, Illinois. His mother was a piano teacher. His father, Louis Katz, Louis N. Katz M.D. was a cardiologist, winner of the Lasker Award and president of the American Physiological Society and American Heart Association. Katz attended the University of Chicago and earned a Bachelor of Arts in 1952. He graduated as a medical doctor from Harvard Medical School in 1956, and did his medical internship at the Massachusetts General Hospital, where he also serveded as medical assistant resident in 1959. He spent 1957-1958 studying protein chemistry in the Laboratory of Christian B. Anfinsen at the National Institutes of Health in Bethesda. Katz later worked in medical research at the University of California at Los Angeles and the Columbia University in New York, becoming ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Kinase A
In cell biology, protein kinase A (PKA) is a family of enzymes whose activity is dependent on cellular levels of cyclic AMP (cAMP). PKA is also known as cAMP-dependent protein kinase (). PKA has several functions in the cell, including regulation of glycogen, sugar, and lipid metabolism. It should not be confused with 5'-AMP-activated protein kinase (AMP-activated protein kinase). History Protein kinase A, more precisely known as adenosine 3',5'-monophosphate (cyclic AMP)-dependent protein kinase, abbreviated to PKA, was discovered by chemists Edmond H. Fischer and Edwin G. Krebs in 1968. They won the Nobel Prize in Physiology or Medicine in 1992 for their work on phosphorylation and dephosphorylation and how it relates to PKA activity. PKA is one of the most widely researched protein kinases, in part because of its uniqueness; out of 540 different protein kinase genes that make up the human kinome, only one other protein kinase, casein kinase 2, is known to exist in a physio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dilated Cardiomyopathy
Dilated cardiomyopathy (DCM) is a condition in which the heart becomes enlarged and cannot pump blood effectively. Symptoms vary from none to feeling tired, leg swelling, and shortness of breath. It may also result in chest pain or fainting. Complications can include heart failure, heart valve disease, or an irregular heartbeat. Causes include genetics, alcohol, cocaine, certain toxins, complications of pregnancy, and certain infections. Coronary artery disease and high blood pressure may play a role, but are not the primary cause. In many cases the cause remains unclear. It is a type of cardiomyopathy, a group of diseases that primarily affects the heart muscle. The diagnosis may be supported by an electrocardiogram, chest X-ray, or echocardiogram. In those with heart failure, treatment may include medications in the ACE inhibitor, beta blocker, and diuretic families. A low salt diet may also be helpful. In those with certain types of irregular heartbeat, blood thinners or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micropeptide
Micropeptides (also referred to as microproteins) are polypeptides with a length of less than 100-150 amino acids that are encoded by short open reading frames (sORFs). In this respect, they differ from many other active small polypeptides, which are produced through the posttranslational cleavage of larger polypeptides. In terms of size, micropeptides are considerably shorter than "canonical" proteins, which have an average length of 330 and 449 amino acids in prokaryotes and eukaryotes, respectively. Micropeptides are sometimes named according to their genomic location. For example, the translated product of an upstream open reading frame (uORF) might be called a uORF-encoded peptide (uPEP). Micropeptides lack an N-terminal signaling sequences, suggesting that they are likely to be localized to the cytoplasm. However, some micropeptides have been found in other cell compartments, as indicated by the existence of transmembrane micropeptides. They are found in both prokaryotes and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympathetic Nervous System
The sympathetic nervous system (SNS) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of the autonomic nervous system, and sometimes considered an independent system. The autonomic nervous system functions to regulate the body's unconscious actions. The sympathetic nervous system's primary process is to stimulate the body's fight or flight response. It is, however, constantly active at a basic level to maintain homeostasis. The sympathetic nervous system is described as being antagonistic to the parasympathetic nervous system which stimulates the body to "feed and breed" and to (then) "rest-and-digest". Structure There are two kinds of neurons involved in the transmission of any signal through the sympathetic system: pre-ganglionic and post-ganglionic. The shorter preganglionic neurons originate in the thoracolumbar division o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarcolipin
Sarcolipin is a micropeptide protein that in humans is encoded by the ''SLN'' gene. Function Sarcoplasmic reticulum Ca2+-ATPases are transmembrane proteins that catalyze the ATP-dependent transport of Ca2+ from the cytosol into the lumen of the sarcoplasmic reticulum in muscle cells. The SLN gene encodes a small transmembrane proteolipid that regulates several sarcoplasmic reticulum Ca2+-ATPases by reducing the accumulation of Ca2+ in the sarcoplasmic reticulum without affecting the rate of ATP hydrolysis. Ablation of sarcolipin increases atrial Ca2+ transient amplitudes and enhanced atrial contractility. Furthermore, atria from sarcolipin- null mice have blunted response to isoproterenol stimulation, implicating sarcolipin as a mediator of beta-adrenergic responses in atria. Sarcolipin is an important mediator of muscle based non shivering thermogenesis (NST). It causes the sarcoplasmic reticulum Ca2+-ATPases to stop pumping Ca2+ ions but continue futilely hydrolysing ATP, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Knockout
A gene knockout (abbreviation: KO) is a genetic technique in which one of an organism's genes is made inoperative ("knocked out" of the organism). However, KO can also refer to the gene that is knocked out or the organism that carries the gene knockout. Knockout organisms or simply knockouts are used to study gene function, usually by investigating the effect of gene loss. Researchers draw inferences from the difference between the knockout organism and normal individuals. The KO technique is essentially the opposite of a gene knock-in. Knocking out two genes simultaneously in an organism is known as a double knockout (DKO). Similarly the terms triple knockout (TKO) and quadruple knockouts (QKO) are used to describe three or four knocked out genes, respectively. However, one needs to distinguish between heterozygous and homozygous KOs. In the former, only one of two gene copies (alleles) is knocked out, in the latter both are knocked out. Methods Knockouts are accomplished throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heart Rate
Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excrete carbon dioxide, but is also modulated by numerous factors, including, but not limited to, genetics, physical fitness, stress or psychological status, diet, drugs, hormonal status, environment, and disease/illness as well as the interaction between and among these factors. It is usually equal or close to the pulse measured at any peripheral point. The American Heart Association states the normal resting adult human heart rate is 60–100 bpm. Tachycardia is a high heart rate, defined as above 100 bpm at rest. Bradycardia is a low heart rate, defined as below 60 bpm at rest. When a human sleeps, a heartbeat with rates around 40–50 bpm is common and is considered normal. When the heart is not beating in a regular pattern, this is ref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stroke Volume
In cardiovascular physiology, stroke volume (SV) is the volume of blood pumped from the left ventricle per beat. Stroke volume is calculated using measurements of ventricle volumes from an echocardiogram and subtracting the volume of the blood in the ventricle at the end of a beat (called end-systolic volume) from the volume of blood just prior to the beat (called end-diastolic volume). The term ''stroke volume'' can apply to each of the two ventricles of the heart, although it usually refers to the left ventricle. The stroke volumes for each ventricle are generally equal, both being approximately 70 mL in a healthy 70-kg man. Stroke volume is an important determinant of cardiac output, which is the product of stroke volume and heart rate, and is also used to calculate ejection fraction, which is stroke volume divided by end-diastolic volume. Because stroke volume decreases in certain conditions and disease states, stroke volume itself correlates with cardiac function. Calculati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
