A coiled coil is a structural motif in proteins in which 2–7 alpha-helices are coiled together like the strands of a rope. Many coiled coil-type proteins are involved in important biological functions, such as the regulation of gene expression — e.g., transcription factors. Notable examples are the oncoproteins c-Fos and c-jun, as well as the muscle protein tropomyosin.
Vimentin is a structural protein that in humans is encoded by the VIM gene. Its name comes from the Latin vimentum which refers to an array of flexible rods.
Enaptin also known as nesprin-1 or synaptic nuclear envelope protein 1 (syne-1) is an actin-binding protein that in humans that is encoded by the SYNE1 gene.
Spectrin is a cytoskeletal protein that lines the intracellular side of the plasma membrane in eukaryotic cells. Spectrin forms pentagonal or hexagonal arrangements, forming a scaffold and playing an important role in maintenance of plasma membrane integrity and cytoskeletal structure. The hexagonal arrangements are formed by tetramers of spectrin subunits associating with short actin filaments at either end of the tetramer. These short actin filaments act as junctional complexes allowing the formation of the hexagonal mesh. The protein is named spectrin since it was first isolated as a major protein component of human red blood cells which had been treated with mild detergents; the detergents lysed the cells and the hemoglobin and other cytoplasmic components were washed out. In the light microscope the basic shape of the red blood cell could still be seen as the spectrin-containing submembranous cytoskeleton preserved the shape of the cell in outline. This became known as a red blood cell "ghost" (spectre), and so the major protein of the ghost was named spectrin.
An intrinsically disordered protein (IDP) is a protein that lacks a fixed or ordered three-dimensional structure, typically in the absence of its macromolecular interaction partners, such as other proteins or RNA. IDPs range from fully unstructured to partially structured and include random coil, molten globule-like aggregates, or flexible linkers in large multi-domain proteins. They are sometimes considered as a separate class of proteins along with globular, fibrous and membrane proteins.
Pleckstrin homology domain or (PHIP) is a protein domain of approximately 120 amino acids that occurs in a wide range of proteins involved in intracellular signaling or as constituents of the cytoskeleton.
Desmoplakin is a protein in humans that is encoded by the DSP gene. Desmoplakin is a critical component of desmosome structures in cardiac muscle and epidermal cells, which function to maintain the structural integrity at adjacent cell contacts. In cardiac muscle, desmoplakin is localized to intercalated discs which mechanically couple cardiac cells to function in a coordinated syncytial structure. Mutations in desmoplakin have been shown to play a role in dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, striate palmoplantar keratoderma, Carvajal syndrome and paraneoplastic pemphigus.
Alpha-actinin-1 is a protein that in humans is encoded by the ACTN1 gene.
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.
Alpha II-spectrin, also known as Spectrin alpha chain, brain is a protein that in humans is encoded by the SPTAN1 gene. Alpha II-spectrin is expressed in a variety of tissues, and is highly expressed in cardiac muscle at Z-disc structures, costameres and at the sarcolemma membrane. Mutations in alpha II-spectrin have been associated with early infantile epileptic encephalopathy-5, and alpha II-spectrin may be a valuable biomarker for Guillain–Barré syndrome and infantile congenital heart disease.
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.
Spectrin beta chain, brain 1 is a protein that in humans is encoded by the SPTBN1 gene.
Microtubule-actin cross-linking factor 1, isoforms 1/2/3/5 is a protein that in humans is encoded by the MACF1 gene.
Spectrin, beta, non-erythrocytic 4, also known as SPTBN4, is a protein that in humans is encoded by the SPTBN4 gene.
Myomesin-1 is a protein that in humans is encoded by the MYOM1 gene. Myomesin-1 is expressed in muscle cells and functions to stabilize the three-dimensional conformation of the thick filament. Embryonic forms of Myomesin-1 have been detected in dilated cardiomyopathy.
Proteins are generally thought to adopt unique structures determined by their amino acid sequences. However, proteins are not strictly static objects, but rather populate ensembles of conformations. Transitions between these states occur on a variety of length scales and time scales, and have been linked to functionally relevant phenomena such as allosteric signaling and enzyme catalysis.
The WW domain, is a modular protein domain that mediates specific interactions with protein ligands. This domain is found in a number of unrelated signaling and structural proteins and may be repeated up to four times in some proteins. Apart from binding preferentially to proteins that are proline-rich, with particular proline-motifs, [AP]-P-P-[AP]-Y, some WW domains bind to phosphoserine- phosphothreonine-containing motifs.
Calponin homology domain is a family of actin binding domains found in both cytoskeletal proteins and signal transduction proteins. The domain is about 100 amino acids in length and is composed of four alpha helices. It comprises the following groups of actin-binding domains:
An array of protein tandem repeats is defined as several adjacent copies having the same or similar sequence motifs. These periodic sequences are generated by internal duplications in both coding and non-coding genomic sequences. Repetitive units of protein tandem repeats are considerably diverse, ranging from the repetition of a single amino acid to domains of 100 or more residues.
