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SEMA4D
Semaphorin-4D (SEMA4D) also known as Cluster of Differentiation 100 (CD100), is a protein of the semaphorin family that in humans is encoded by the ''SEMA4D'' gene. Function Semaphorin 4D (Sema 4D) is an axon guidance molecule which is secreted by oligodendrocytes and induces growth cone collapse in the central nervous system. By binding plexin B1 receptor it functions as an R-Ras GTPase-activating protein (GAP) and repels axon growth cones in both the mature central nervous system. In the immune system, CD100 binds CD72 to activate B cells and dendritic cells, though much about this interaction is still under investigation. During skin damage repairs, SEMA4D interacts with Plexin B2 on Gamma delta T cells to play a role in the healing process. See also * Cluster of differentiation The cluster of differentiation (also known as cluster of designation or classification determinant and often abbreviated as CD) is a protocol used for the identification and investigation of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semaphorin
Semaphorins are a class of secreted and membrane proteins that were originally identified as axonal growth cone guidance molecules. They primarily act as short-range inhibitory signals and signal through multimeric receptor (biochemistry), receptor complexes. Semaphorins are usually cues to deflect axons from inappropriate regions, especially important in the nervous system, neural system development. The major class of proteins that act as their receptors are called plexins, with Neuropilin, neuropilins as their co-receptors in many cases. The main receptors for semaphorins are plexins, which have established roles in regulating Rho-family GTPases. Recent work shows that plexins can also influence RRAS, R-Ras, which, in turn, can regulate integrins. Such regulation is probably a common feature of semaphorin signalling and contributes substantially to our understanding of semaphorin biology. Every semaphorin is characterised by the expression of a specific region of about 500 amin ... [...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 residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 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 pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and non-coding genes. During gene expression (the synthesis of Gene product, RNA or protein from a gene), DNA is first transcription (biology), copied into RNA. RNA can be non-coding RNA, directly functional or be the intermediate protein biosynthesis, template for the synthesis of a protein. The transmission of genes to an organism's offspring, is the basis of the inheritance of phenotypic traits from one generation to the next. These genes make up different DNA sequences, together called a genotype, that is specific to every given individual, within the gene pool of the population (biology), population of a given species. The genotype, along with environmental and developmental factors, ultimately determines the phenotype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axon Guidance
Axon guidance (also called axon pathfinding) is a subfield of neural development concerning the process by which neurons send out axons to reach their correct targets. Axons often follow very precise paths in the nervous system, and how they manage to find their way so accurately is an area of ongoing research. Axon growth takes place from a region called the growth cone and reaching the axon target is accomplished with relatively few guidance molecules. Growth cone receptors respond to the guidance cues. Mechanisms Growing axons have a highly motile structure at the growing tip called the growth cone, which responds to signals in the extracellular environment that instruct the axon in which direction to grow. These signals, called guidance cues, can be fixed in place or diffusible; they can attract or repel axons. Growth cones contain receptors that recognize these guidance cues and interpret the signal into a chemotropic response. The general theoretical framework is that wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligodendrocyte
Oligodendrocytes (), also known as oligodendroglia, are a type of neuroglia whose main function is to provide the myelin sheath to neuronal axons in the central nervous system (CNS). Myelination gives metabolic support to, and insulates the axons of most vertebrates. A single oligodendrocyte can extend its Cellular extensions, processes to cover up to 40 axons, that can include multiple adjacent axons. The myelin sheath is segmented along the axon's length at gaps known as the nodes of Ranvier. In the peripheral nervous system the myelination of axons is carried out by Schwann cells. Oligodendrocytes are found exclusively in the CNS, which comprises the brain and spinal cord. They are the most widespread cell lineage, including oligodendrocyte progenitor cells, pre-myelinating cells, and mature myelinating oligodendrocytes in the CNS white matter. Non-myelinating oligodendrocytes are found in the grey matter surrounding and lying next to neuronal cell bodies. They are known as neu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Growth Cone
A growth cone is a large actin-supported extension of a developing or regenerating neurite seeking its synaptic target. It is the growth cone that drives axon growth. Their existence was originally proposed by Spanish histologist Santiago Ramón y Cajal based upon stationary images he observed under the microscope. He first described the growth cone based on fixed cells as "a concentration of protoplasm of conical form, endowed with amoeboid movements" (Cajal, 1890). Growth cones are situated on the tips of neurites, either dendrites or axons, of the nerve cell. The sensory, motor, integrative, and adaptive functions of growing axons and dendrites are all contained within this specialized structure. Structure The morphology of the growth cone can be easily described by using the hand as an analogy. The fine extensions of the growth cone are pointed filopodia known as microspikes. The filopodia are like the "fingers" of the growth cone; they contain bundles of actin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Nervous System
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all parts of the bodies of bilateria, bilaterally symmetric and triploblastic animals—that is, all multicellular animals except sponges and Coelenterata, diploblasts. It is a structure composed of nervous tissue positioned along the Anatomical_terms_of_location#Rostral,_cranial,_and_caudal, rostral (nose end) to caudal (tail end) axis of the body and may have an enlarged section at the rostral end which is a brain. Only arthropods, cephalopods and vertebrates have a true brain, though precursor structures exist in onychophorans, gastropods and lancelets. The rest of this article exclusively discusses the vertebrate central nervous system, which is radically distinct from all other animals. Overview In vertebrates, the brain and spinal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PLXNB1
Plexin B1 is a protein of the plexin family that in humans is encoded by the ''PLXNB1'' gene. Function Within neural tissues, the plexin A plexin is a protein which acts as a receptor for semaphorin family signaling proteins. It is classically known for its expression on the surface of axon growth cones and involvement in signal transduction to steer axon growth away from the sour ... family serves as transmembrane receptors for Semaphorins. Outside of neural tissues, Plexin B1 is implicated in the control of cell migration. Interactions PLXNB1 has been shown to interact with ARHGEF12, Rnd1 and ARHGEF11. References * Chapoval SP, Hritzo M, Qi X, Tamagnone L, Golding A and Keegan AD. "Semaphorin 4A Stabilizes Human Regulatory T Cell Phenotype via Plexin B1". ImmunoHorizons, February 1, 2019, 3 (2) 71-87; Further reading * * * * * * * * * * * * * * * * External links * {{gene-3-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CD72
CD72 (Cluster of Differentiation 72), also known in murine biology as Lyb-2, is a protein active in the immune system of animals. It consists of two identical halves, each of about 39-43 kD, and is a C-type lectin. Its primarily locus of expression is B-cells (from the pro-B through the mature B-cell stage), where it appears to mediate aspects of B-cell - T-cell interaction. It is a ligand for CD5. CD72 is a regulatory protein on B lymphocytes. The cytoplasmic tail of CD72 contains two potential immunoreceptor tyrosine-based inhibitory motifs, one of which has been shown to recruit the tyrosine phosphatase SHP- 1. These features suggest a negative regulatory role for CD72. CD72 is a nonredundant regulator of B-cell development and a negative regulator of B-cell responsiveness. See also * Cluster of differentiation References External links Dr. Jane Parnes lab at Stanford University Leland Stanford Junior University, commonly referred to as Stanford University, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
B Cell
B cells, also known as B lymphocytes, are a type of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted or inserted into the plasma membrane where they serve as a part of B-cell receptors. When a naïve or memory B cell is activated by an antigen, it proliferates and differentiates into an antibody-secreting effector cell, known as a plasmablast or plasma cell. In addition, B cells Antigen presentation, present antigens (they are also classified as professional Antigen-presenting cell, antigen-presenting cells, APCs) and secrete cytokines. In mammals B cells Cellular differentiation, mature in the bone marrow, which is at the core of most bones. In birds, B cells mature in the bursa of Fabricius, a lymphoid organ where they were first discovered by Chang and Glick, which is why the ''B'' stands for ''bursa'' and not ''bone marrow'', as commonly believed. B cells, unl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendritic Cell
A dendritic cell (DC) is an antigen-presenting cell (also known as an ''accessory cell'') of the mammalian immune system. A DC's main function is to process antigen material and present it on the cell surface to the T cells of the immune system. They act as messengers between the innate and adaptive immune systems. Dendritic cells are present in tissues that are in contact with the body's external environment, such as the skin, and the inner lining of the nose, lungs, stomach and intestines. They can also be found in an immature and mature state in the blood. Once activated, they migrate to the lymph nodes, where they interact with T cells and B cells to initiate and shape the adaptive immune response. At certain development stages they grow branched projections, the '' dendrites,'' that give the cell its name (δένδρον or déndron being Greek for 'tree'). While similar in appearance to the dendrites of neurons, these are structures distinct from them. Immature dendr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different developmental origin, structure and chemical composition. The adjective cutaneous means "of the skin" (from Latin ''cutis'' 'skin'). In mammals, the skin is an organ of the integumentary system made up of multiple layers of ectodermal tissue and guards the underlying muscles, bones, ligaments, and internal organs. Skin of a different nature exists in amphibians, reptiles, and birds. Skin (including cutaneous and subcutaneous tissues) plays crucial roles in formation, structure, and function of extraskeletal apparatus such as horns of bovids (e.g., cattle) and rhinos, cervids' antlers, giraffids' ossicones, armadillos' osteoderm, and os penis/ os clitoris. All mammals have some hair on their skin, even marine mammals like whales, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
