Four and a half LIM domains protein 1 is a protein that in humans is encoded by the FHL1 gene. [5] [6] [7]
LIM proteins, named for 'LIN11, ISL1, and MEC3,' are defined by the possession of a highly conserved double zinc finger motif called the LIM domain. [7]
FHL1 has been shown to be heavily expressed in skeletal and cardiac muscles. [8] In 2008 this was borne out by the discovery that defects in the FHL1 gene are responsible for a number of Muscular dystrophy-like muscle disorders, ranging from severe, childhood onset diseases through to adult-onset disorders similar to Limb girdle muscular dystrophy. At least 15 disease-causing mutations in this gene have been discovered. [9] At present different research groups are using different terminology for these disorders, which include:
Titin 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.
Dysferlin also known as dystrophy-associated fer-1-like protein is a protein that in humans is encoded by the DYSF gene. Dysferlin is linked with plasma membrane repair., stabilization of calcium signaling and the development of the T-tubule system of the muscle A defect in the DYSF gene, located on chromosome 2p12-14, results in several types of muscular dystrophy; including Miyoshi myopathy (MM), Limb-girdle muscular dystrophy type 2B (LGMD2B) and Distal Myopathy (DM). A reduction or absence of dysferlin, termed dysferlinopathy, usually becomes apparent in the third or fourth decade of life and is characterised by weakness and wasting of various voluntary skeletal muscles. Pathogenic mutations leading to dysferlinopathy can occur throughout the DYSF gene.
Congenital myopathy is a very broad term for any muscle disorder present at birth. This defect primarily affects skeletal muscle fibres and causes muscular weakness and/or hypotonia. Congenital myopathies account for one of the top neuromuscular disorders in the world today, comprising approximately 6 in 100,000 live births every year. As a whole, congenital myopathies can be broadly classified as follows:
Four and a half LIM domains protein 2 also known as FHL-2 is a protein that in humans is encoded by the FHL2 gene. LIM proteins contain a highly conserved double zinc finger motif called the LIM domain.
Cux1 is a homeodomain protein that in humans is encoded by the CUX1 gene.
Alpha-7 integrin is a protein that in humans is encoded by the ITGA7 gene. Alpha-7 integrin is critical for modulating cell-matrix interactions. Alpha-7 integrin is highly expressed in cardiac muscle, skeletal muscle and smooth muscle cells, and localizes to Z-disc and costamere structures. Mutations in ITGA7 have been associated with congenital myopathies and noncompaction cardiomyopathy, and altered expression levels of alpha-7 integrin have been identified in various forms of muscular dystrophy.
β-Tropomyosin, also known as tropomyosin beta chain is a protein that in humans is encoded by the TPM2 gene. β-tropomyosin is striated muscle-specific coiled coil dimer that functions to stabilize actin filaments and regulate muscle contraction.
Troponin I, fast skeletal muscle is a protein that in humans is encoded by the TNNI2 gene.
Slow skeletal muscle troponin T (sTnT) is a protein that in humans is encoded by the TNNT1 gene.
Myotilin is a protein that in humans is encoded by the MYOT gene. Myotilin also known as TTID is a muscle protein that is found within the Z-disc of sarcomeres.
Leucyl-tRNA synthetase, cytoplasmic is an enzyme that in humans is encoded by the LARS gene.
PDZ and LIM domain protein 1 is a protein that in humans is encoded by the PDLIM1 gene.
Four and a half LIM domains protein 3 is a protein that in humans is encoded by the FHL3 gene.
Cysteine and glycine-rich protein 3 also known as cardiac LIM protein (CLP) or muscle LIM protein (MLP) is a protein that in humans is encoded by the CSRP3 gene.
LIM domain binding 3 (LDB3), also known as Z-band alternatively spliced PDZ-motif (ZASP), is a protein which in humans is encoded by the LDB3 gene. ZASP belongs to the Enigma subfamily of proteins and stabilizes the sarcomere during contraction, through interactions with actin in cardiac and skeletal muscles. Mutations in the ZASP gene has been associated with several muscular diseases.
Cysteine-rich protein 2 is a protein that in humans is encoded by the CRIP2 gene.
LIM domain-binding protein 2 is a protein that in humans is encoded by the LDB2 gene.
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.
Ryanodine receptor 1 (RYR-1) also known as skeletal muscle calcium release channel or skeletal muscle-type ryanodine receptor is one of a class of ryanodine receptors and a protein found primarily in skeletal muscle. In humans, it is encoded by the RYR1 gene.
Myogenic factor 6 is a protein that in humans is encoded by the MYF6 gene. This gene is also known in the biomedical literature as MRF4 and herculin. MYF6 is a myogenic regulatory factor (MRF) involved in the process known as myogenesis.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.