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ACTN2
Alpha-actinin-2 is a protein which in humans is encoded by the ''ACTN2'' gene. This gene encodes an alpha-actinin isoform that is expressed in both skeletal and cardiac muscles and functions to anchor myofibrillar actin thin filaments and titin to Z-discs. Structure Alpha-actinin-2 is a 103.8 kDa protein composed of 894 amino acids. Each molecule is rod-shaped (35 nm in length) and it homodimerizes in an anti-parallel fashion. Each monomer has an N-terminal actin-binding region composed of two calponin homology domains, two C-terminal EF hand domains, and four tandem spectrin-like repeats form the rod domain in the central region of the molecule. The high-resolution crystal structure of human alpha-actinin 2 at 3.5 Å was recently resolved. Alpha actinins belong to the spectrin gene superfamily which represents a diverse group of actin-binding cytoskeletal proteins, including spectrin, dystrophin, utrophin and fimbrin. Skeletal, cardiac, and smooth muscle isoforms are local ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MYOT
Myotilin is a protein that in humans is encoded by the ''MYOT'' gene. Myotilin (myofibrillar titin-like protein) also known as TTID (TiTin Immunoglobulin Domain) is a muscle protein that is found within the sarcomere, Z-disc of sarcomeres. Structure Myotilin is a 55.3 kDa protein composed of 496 amino acids. Myotilin was originally identified as a novel ACTN2, alpha-actinin binding partner with two immunoglobulin, Ig-like domains, that localized to the sarcomere, Z-disc. The I-type immunoglobulin, Ig-like domains reside at the C-terminal half, and are most homologous to immunoglobulin, Ig domains 2-3 of palladin and immunoglobulin, Ig domains 4-5 of MYPN, myopalladin and more distantly related to sarcomere, Z-disc immunoglobulin, Ig domains 7 and 8 of titin. The C-terminal region hosts the binding sites for Z-band proteins, and 2 immunoglobulin, Ig domains are the site of homodimerization for myotilin. By contrast, the N-terminal part of myotilin is unique, consisting of a serine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MYPN
Myopalladin is a protein that in humans is encoded by the ''MYPN'' gene. Myopalladin is a muscle protein responsible for tethering proteins at the Z-disc and for communicating between the sarcomere and the nucleus in cardiac and skeletal muscle Structure Myopalladin is a 145.2 kDa protein composed of 1320 amino acids. Myopalladin has five Ig-like repeats within the protein, and a proline-rich domain. Myopalladin binds the Src homology domain of nebulette and nebulin and tethers it to alpha-actinin via its C-terminal domain binding to the EF hand domains of alpha-actinin. The N-terminal region of myopalladin binds to the nuclear protein CARP, known to regulate gene expression in muscle. It also has been shown to bind ANKRD23. Function Myopalladin has dual subcellular localization, residing in both the nucleus and sarcomere/ I-bands in muscle. Accordingly, myopalladin has functions in both sarcomere assembly and in control of gene expression. Specifics of these functions we ... [...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] |
ADAM12
Disintegrin and metalloproteinase domain-containing protein 12 (previously Meltrin) is an enzyme that in humans is encoded by the ''ADAM12'' gene. ADAM12 has two splice variants: ADAM12-L, the long form, has a transmembrane region and ADAM12-S, a shorter variant, is soluble and lacks the transmembrane and cytoplasmic domains. Function This gene encodes a member of the ADAM (a disintegrin and metalloprotease) protein family. Members of this family are membrane-anchored proteins structurally related to snake venom disintegrins, and have been implicated in a variety of biological processes involving cell-cell and cell-matrix interactions, including fertilization, muscle development, and neurogenesis. This gene has two alternatively spliced transcripts: a shorter secreted form and a longer membrane-bound form. The shorter form is found to stimulate myogenesis. Clinical Significance ADAM 12, a metalloprotease that binds insulin growth factor binding protein-3 (IGFBP-3), appears ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SYNPO2
Myopodin protein, also called Synaptopodin-2 is a protein that in humans is encoded by the ''SYNPO2'' gene. Myopodin is expressed in cardiac, smooth muscle and skeletal muscle, and localizes to Z-disc structures. Structure Myopodin is a 117.4 kDa protein composed of 1093 amino acids, although four alternatively-spliced isoforms have been described. Myopodin contains one PPXY motif, multiple PXXP motifs, and two potential nuclear localization sequences (one N-terminal and one C-terminal). PPXY motifs have been shown to mediate interactions, and PXXP motifs represent potential sites of interaction for SH3 domain-containing proteins. Myopodin contains a novel actin binding site (between amino acids 410 and 563) in the center of the protein. Function During myotube differentiation, myopodin interacts with stress fibers prior to co-localizing with alpha actinin-2 at Z-discs in mature striated muscle cells. Myopodin has been shown to shuttle between the nucleus and cytoplasm in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EF Hand
The EF hand is a helix–loop–helix structural domain or ''motif'' found in a large family of calcium-binding proteins. The EF-hand motif contains a helix–loop–helix topology, much like the spread thumb and forefinger of the human hand, in which the Ca2+ ions are coordinated by ligands within the loop. The motif takes its name from traditional nomenclature used in describing the protein parvalbumin, which contains three such motifs and is probably involved in muscle relaxation via its calcium-binding activity. The EF-hand consists of two alpha helices linked by a short loop region (usually about 12 amino acids) that usually binds calcium ions. EF-hands also appear in each structural domain of the signaling protein calmodulin and in the muscle protein troponin-C. Calcium ion binding site The calcium ion is coordinated in a pentagonal bipyramidal configuration. The six residues involved in the binding are in positions 1, 3, 5, 7, 9 and 12; these residues are denoted by X ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinin
Actinin is a microfilament protein. Alpha-actinin-1 is necessary for the attachment of actin myofilaments to the Z-lines in skeletal muscle cells, and to the dense bodies in smooth muscle cells. The functional protein is an anti-parallel dimer, which cross-links the thin filaments in adjacent sarcomeres, and therefore coordinates contractions between sarcomeres in the horizontal axis. The non-sarcomeric alpha-actinins, encoded by ''ACTN1'' and ''ACTN4'', are widely expressed. ''ACTN2'' expression is found in both cardiac and skeletal muscle, whereas ''ACTN3'' is limited to the latter. Both ends of the rod-shaped alpha-actinin dimer contain actin-binding domains. Mutations in ''ACTN4'' can cause the kidney disease focal segmental glomerulosclerosis (FSGS). See also * Actin * Muscle contraction Muscle contraction is the activation of tension-generating sites within muscle cells. In physiology, muscle contraction does not necessarily mean muscle shortening because muscle ten ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DISC1
Disrupted in schizophrenia 1 is a protein that in humans is encoded by the ''DISC1'' gene. In coordination with a wide array of interacting partners, DISC1 has been shown to participate in the regulation of cell proliferation, differentiation, migration, neuronal axon and dendrite outgrowth, mitochondrial transport, fission and/or fusion, and cell-to-cell adhesion. Several studies have shown that unregulated expression or altered protein structure of DISC1 may predispose individuals to the development of schizophrenia, clinical depression, bipolar disorder, and other psychiatric conditions. The cellular functions that are disrupted by permutations in DISC1, which lead to the development of these disorders, have yet to be clearly defined and are the subject of current ongoing research. Although, recent genetic studies of large schizophrenia cohorts have failed to implicate DISC1 as a risk gene at the gene level, the DISC1 interactome gene set was associated with schizophrenia, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GRIN2B
Glutamate MDAreceptor subunit epsilon-2, also known as ''N''-methyl D-aspartate receptor subtype 2B (NMDAR2B or NR2B), is a protein that in humans is encoded by the ''GRIN2B'' gene. NMDA receptors ''N''-methyl-D-aspartate (NMDA) receptors are a class of ionotropic glutamate receptors. The NMDA receptor channel has been shown to be involved in long-term potentiation, an activity-dependent increase in the efficiency of synaptic transmission thought to underlie certain kinds of memory and learning. NMDA receptor channels are heterotetramers composed of two molecules of the key receptor subunit NMDAR1 (GRIN1) and two drawn from one or more of the four NMDAR2 subunits: NMDAR2A ( GRIN2A), NMDAR2B (GRIN2B), NMDAR2C ( GRIN2C), and NMDAR2D ( GRIN2D). The NR2 subunit acts as the agonist binding site for glutamate, one of the predominant excitatory neurotransmitter receptors in the mammalian brain. Function NR2B has been associated with age- and visual-experience-dependent plasticity in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ACTN3
Alpha-actinin-3, also known as alpha-actinin skeletal muscle isoform 3 or F-actin cross-linking protein, is a protein that in humans is encoded by the ''ACTN3'' gene (named sprinter gene, speed gene or athlete gene) located on chromosome 11. All people have two copies (alleles) of this gene. Alpha-actinin is an actin-binding protein with multiple roles in different cell types. This gene expression is limited to skeletal muscle. It is localized to the Z-disc and analogous dense bodies, where it helps to anchor the myofibrillar actin filaments. Fast versus slow twitch muscle fibers Skeletal muscle is composed of long cylindrical cells called muscle fibers. There are two types of muscle fibers, slow twitch or muscle contraction (type I) and fast twitch (type II). Slow twitch fibers are more efficient in using oxygen to generate energy, while fast twitch fibers are less efficient. However, fast twitch fibers fire more rapidly, allowing them to generate more power than slow twitch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titin
Titin (contraction for Titan protein) (also called connectin) is a protein that in humans is encoded by the ''TTN'' gene. Titin is a giant protein, greater than 1 µm in length, that functions as a molecular spring that is responsible for the passive elasticity of muscle. It comprises 244 individually folded protein domains connected by unstructured peptide sequences. These domains unfold when the protein is stretched and refold when the tension is removed. Titin is important in the contraction of striated muscle tissues. It connects the Z line to the M line in the sarcomere. The protein contributes to force transmission at the Z line and resting tension in the I band region. It limits the range of motion of the sarcomere in tension, thus contributing to the passive stiffness of muscle. Variations in the sequence of titin between different types of striated muscle (cardiac or skeletal) have been correlated with differences in the mechanical properties of these muscles. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDLIM3
Actin-associated LIM protein (ALP), also known as PDZ and LIM domain protein 3 is a protein that in humans is encoded by the ''PDLIM3'' gene. ALP is highly expressed in cardiac and skeletal muscle, where it localizes to Z-discs and intercalated discs. ALP functions to enhance the crosslinking of actin by alpha-actinin-2 and also appears to be essential for right ventricular chamber formation and contractile function. Structure ALP exists primarily as two alternatively spliced variants; a 39.2 kDa (364 amino acids) protein in skeletal muscle and a 34.3 kDa (316 amino acids) protein in cardiac muscle and smooth muscle. ALP has a N-terminal PDZ domain and a C-terminal LIM domain. In addition, the ALP subfamily contains a specific 34 amino acid domain named the ALP-like motif, containing protein kinase C consensus sequences. The PDZ domain of ALP binds to alpha actinin-2, specifically to its spectrin-like repeats. The PDZ domain is a motif composed of 80-120 amino acids with conser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
