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Rab (G-protein)
The Rab family of proteins is a member of the Ras superfamily of small G proteins. Approximately 70 types of Rabs have now been identified in humans. Rab proteins generally possess a GTPase fold, which consists of a six-stranded beta sheet which is flanked by five alpha helices. Rab GTPases regulate many steps of membrane trafficking, including vesicle formation, vesicle movement along actin and tubulin networks, and membrane fusion. These processes make up the route through which cell surface proteins are trafficked from the Golgi to the plasma membrane and are recycled. Surface protein recycling returns proteins to the surface whose function involves carrying another protein or substance inside the cell, such as the transferrin receptor, or serves as a means of regulating the number of a certain type of protein molecules on the surface. Function Rab proteins are peripheral membrane proteins, anchored to a membrane via a lipid group covalently linked to an amino acid. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid resid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rab GDP Dissociation Inhibitors
In molecular biology, the Guanosine dissociation inhibitors (GDIs) constitute a family of small GTPases that serve a regulatory role in vesicular membrane traffic. GDIs bind to the GDP-bound form of Rho and Rab small GTPases and not only prevent exchange (maintaining the small GTPase in an off-state), but also prevent the small GTPase from localizing at the membrane, which is their place of action. This inhibition can be removed by the action of a GDI displacement factor. GDIs also inhibit cdc42 by binding to its tail and preventing its insertion into membranes; hence it cannot trigger WASPs and cannot lead to nucleation of F-actin. The GDIs' C-terminal geranylgeranylation is crucial for their membrane association and function. This post-translational modification is catalysed by Rab geranylgeranyl transferase (Rab-GGTase), a multi-subunit enzyme that contains a catalytic heterodimer and an accessory component, termed Rab escort protein (REP)-1. REP-1 presents newly synthesised ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RAB2B
Ras-related protein Rab-2B is a protein that in humans is encoded by the RAB2B gene. RAB2B is required for protein transport from the endoplasmic reticulum to the Golgi complex. It belongs to the small GTPase superfamily, specifically to the RAB protein family. Small GTPases are a type of hydrolase enzymes that can attach to a GTP to form a GDP. This process makes small GTPases active when bonded to a GTP and inactive when bonded to a GDP. Inside this small GTPase superfamily we can find the RAS subfamily. This family is divided into 5 groups: Ras, Rho, Ran, Rab and Arf GTPases. RAB2B’s main function is regulating vesicle transport and membrane fusion. Structure RAB2B is a human protein whose gene is located in the fourteenth chromosome. It has a core made of basic elements such as oxygen, carbon, nitrogen and phosphorus. Its secondary structure contains eight alpha helix and six beta strands. Moreover, it has attached a magnesium ion and a GDP. Mature RAB2B contains three po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RAB2A
Ras-related protein Rab-2A is a protein that in humans is encoded by the ''RAB2A'' gene. Function Members of the Rab protein family are nontransforming monomeric GTP-binding proteins of the Ras superfamily that contain 4 highly conserved regions involved in GTP binding and hydrolysis. Rabs are prenylated, membrane-bound proteins involved in vesicular fusion and trafficking. The mammalian RAB proteins show striking similarities to the S. cerevisiae YPT1 and SEC4 proteins, Ras-related GTP-binding proteins involved in the regulation of secretion. upplied by OMIMref name="entrez" /> Interactions RAB2A has been shown to interact with GOLGA2 Golgin subfamily A member 2 is a protein that in humans is encoded by the ''GOLGA2'' gene. Function The Golgi apparatus, which participates in glycosylation and transport of proteins and lipids in the secretory pathway, consists of a series of .... References Further reading * * * * * * * * * * * * * * * {{ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parkinson's Disease
Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms become more common. The most obvious early symptoms are tremor, rigidity, slowness of movement, and difficulty with walking. Cognitive and behavioral problems may also occur with Depression (mood), depression, anxiety, and apathy occurring in many people with PD. Parkinson's disease dementia becomes common in the advanced stages of the disease. Those with Parkinson's can also have problems with their sleep and sensory systems. The motor symptoms of the disease result from the death of cells in the substantia nigra, a region of the midbrain, leading to a dopamine deficit. The cause of this cell death is poorly understood, but involves the build-up of protein, misfolded proteins into Lewy bodies in the neurons. Collectively, the main motor sym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastric Cancer
Stomach cancer, also known as gastric cancer, is a cancer that develops from the lining of the stomach. Most cases of stomach cancers are gastric carcinomas, which can be divided into a number of subtypes, including gastric adenocarcinomas. Lymphomas and mesenchymal tumors may also develop in the stomach. Early symptoms may include heartburn, upper abdominal pain, nausea, and loss of appetite. Later signs and symptoms may include weight loss, yellowing of the skin and whites of the eyes, vomiting, difficulty swallowing, and blood in the stool, among others. The cancer may spread from the stomach to other parts of the body, particularly the liver, lungs, bones, lining of the abdomen, and lymph nodes. The most common cause is infection by the bacterium ''Helicobacter pylori'', which accounts for more than 60% of cases. Certain types of ''H. pylori'' have greater risks than others. Smoking, dietary factors such as pickled vegetables and obesity are other risk factors. Abou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcinogenesis
Carcinogenesis, also called oncogenesis or tumorigenesis, is the formation of a cancer, whereby normal cells are transformed into cancer cells. The process is characterized by changes at the cellular, genetic, and epigenetic levels and abnormal cell division. Cell division is a physiological process that occurs in almost all tissues and under a variety of circumstances. Normally, the balance between proliferation and programmed cell death, in the form of apoptosis, is maintained to ensure the integrity of tissues and organs. According to the prevailing accepted theory of carcinogenesis, the somatic mutation theory, mutations in DNA and epimutations that lead to cancer disrupt these orderly processes by interfering with the programming regulating the processes, upsetting the normal balance between proliferation and cell death. This results in uncontrolled cell division and the evolution of those cells by natural selection in the body. Only certain mutations lead to canc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Short-term Memory
Short-term memory (or "primary" or "active memory") is the capacity for holding a small amount of information in an active, readily available state for a short interval. For example, short-term memory holds a phone number that has just been recited. The duration of short-term memory (absent rehearsal or active maintenance) is estimated to be on the order of seconds. The commonly cited capacity of 7 items, found in Miller's Law, has been superseded by 4±1 items. In contrast, long-term memory holds information indefinitely. Short-term memory is not the same as working memory, which refers to structures and processes used for temporarily storing and manipulating information. Stores The idea of separate memories for short-term and long-term storage originated in the 19th century. A model of memory developed in the 1960s assumed that all memories are formed in one store and transfer to others store after a small period of time. This model is referred to as the "modal model", mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GDI1
Rab GDP dissociation inhibitor alpha is a protein that in humans is encoded by the ''GDI1'' gene. Function GDP dissociation inhibitors are proteins that regulate the GDP-GTP exchange reaction of members of the rab family, small GTP-binding proteins of the ras superfamily, that are involved in vesicular trafficking of molecules between cellular organelles. GDIs slow the rate of dissociation of GDP from rab proteins and release GDP from membrane-bound rabs. GDI1 is expressed primarily in neural and sensory tissues. Mutations in GDI1 have been linked to X-linked nonspecific mental retardation. Rab GTPases cycles between the cytosolic compartment, where it is bound to a protein called GDI (GDP Dissociation Inhibitor), and the membrane, where it interacts with a receptor, a nucleotide exchange factor, a GAP (GTPase Activating Protein) and probably other factors that link it to the appropriate SNARE. GDI is non-specific with respect to the rab it binds. However, the exchanger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intellectual Disability
Intellectual disability (ID), also known as general learning disability in the United Kingdom and formerly mental retardation, Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010). is a generalized neurodevelopmental disorder characterized by significantly impaired intellectual and adaptive functioning. It is defined by an IQ under 70, in addition to deficits in two or more adaptive behaviors that affect everyday, general living. Intellectual functions are defined under DSM-V as reasoning, problem‑solving, planning, abstract thinking, judgment, academic learning, and learning from instruction and experience, and practical understanding confirmed by both clinical assessment and standardized tests. Adaptive behavior is defined in terms of conceptual, social, and practical skills involving tasks performed by people in their everyday lives. Intellectual disability is subdivided into syndromic intellectual disability, in which intellectual deficits associated with other medical and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-linked
Sex linked describes the sex-specific patterns of inheritance and presentation when a gene mutation (allele) is present on a sex chromosome (allosome) rather than a non-sex chromosome ( autosome). In humans, these are termed X-linked recessive, X-linked dominant and Y-linked. The inheritance and presentation of all three differ depending on the sex of both the parent and the child. This makes them characteristically different from autosomal dominance and recessiveness. There are many more X-linked conditions than Y-linked conditions, since humans have several times as many genes on the X chromosome than the Y chromosome. Only females are able to be carriers for X-linked conditions; males will always be affected by any X-linked condition, since they have no second X chromosome with a healthy copy of the gene. As such, X-linked recessive conditions affect males much more commonly than females. In X-linked recessive inheritance, a son born to a carrier mother and an unaffected ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
