4dx2 | pdb_00004dx2
Crystal structure of the human TRPV4 ankyrin repeat domain
Structural highlights
Disease[TRPV4_HUMAN] Spondylometaphyseal dysplasia, Kozlowski type;Familial digital arthropathy-brachydactyly;Autosomal dominant brachyolmia;Autosomal dominant congenital benign spinal muscular atrophy;Parastremmatic dwarfism;Spondyloepiphyseal dysplasia, Maroteaux type;Autosomal dominant Charcot-Marie-Tooth disease type 2C;Metatropic dysplasia. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. Function[TRPV4_HUMAN] Non-selective calcium permeant cation channel probably involved in osmotic sensitivity and mechanosensitivity. Activation by exposure to hypotonicity within the physiological range exhibits an outward rectification. Also activated by low pH, citrate and phorbol esters. Increase of intracellular Ca(2+) potentiates currents. Channel activity seems to be regulated by a calmodulin-dependent mechanism with a negative feedback mechanism. Promotes cell-cell junction formation in skin keratinocytes and plays an important role in the formation and/or maintenance of functional intercellular barriers. Acts as a regulator of intracellular Ca(2+) in synoviocytes. Plays an obligatory role as a molecular component in the nonselective cation channel activation induced by 4-alpha-phorbol 12,13-didecanoate and hypotonic stimulation in synoviocytes and also regulates production of IL-8.[1] [2] [3] Publication Abstract from PubMedThe TRPV4 calcium-permeable cation channel plays important physiological roles in osmosensation, mechanosensation, cell barrier formation, and bone homeostasis. Recent studies reported that mutations in TRPV4, including some in its ankyrin repeat domain (ARD), are associated with human inherited diseases including neuropathies and skeletal dysplasias, probably due to increased constitutive activity of the channel. TRPV4 activity is regulated by the binding of calmodulin and small molecules such as ATP to the ARD in its cytoplasmic N-terminus. We determined structures of ATP-free and -bound forms of human TRPV4-ARD and compared them with available TRPV-ARD structures. The third inter-repeat loop region (Finger 3 loop) is flexible and may act as a switch to regulate the channel activity. Comparisons of TRPV-ARD structures also suggest an evolutionary link between ARD structure and ATP binding ability. Thermal stability analyses and molecular dynamics (MD) simulations suggest that ATP increases stability in TRPV-ARDs that can bind ATP. Biochemical analyses of a large panel of TRPV4-ARD mutations associated with human inherited diseases showed that some impaired thermal stability while others reduced ATP binding ability, suggesting molecular mechanisms for the diseases. Structural and biochemical consequences of disease-causing mutations in the ankyrin repeat domain of the human TRPV4 channel.,Inada H, Procko E, Sotomayor M, Gaudet R Biochemistry. 2012 Jun 15. PMID:22702953[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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