Popdc (Popeye-domain-containing) genes encode membrane-bound proteins and are abundantly present in cardiac myocytes and in skeletal muscle fibres. Functional analysis of Popdc1 (Bves) and Popdc2 in mice and of popdc2 in zebrafish revealed an overlapping role for proper electrical conduction in the heart and maintaining structural integrity of skeletal muscle. Popdc proteins mediate cAMP signalling and modulate the biological activity of interacting proteins. The two-pore channel TREK-1 interacts with all three Popdc proteins. In Xenopus oocytes, the presence of Popdc proteins causes an enhanced membrane transport leading to an increase in TREK-1 current, which is blocked when cAMP levels are increased. Another important Popdc-interacting protein is caveolin 3, and the loss of Popdc1 affects caveolar size. Thus a family of membrane-bound cAMP-binding proteins has been identified, which modulate the subcellular localization of effector proteins involved in organizing signalling complexes and assuring proper membrane physiology of cardiac myocytes.
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http://dx.doi.org/10.1042/BST20130264 | DOI Listing |
Acta Physiol (Oxf)
October 2024
Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA.
Aim: To identify the physiological role of the acid-base sensing enzyme, soluble adenylyl cyclase (sAC), in red blood cells (RBC) of the model teleost fish, rainbow trout.
Methods: We used: (i) super-resolution microscopy to determine the subcellular location of sAC protein; (ii) live-cell imaging of RBC intracellular pH (pH) with specific sAC inhibition (KH7 or LRE1) to determine its role in cellular acid-base regulation; (iii) spectrophotometric measurements of haemoglobin-oxygen (Hb-O) binding in steady-state conditions; and (iv) during simulated arterial-venous transit, to determine the role of sAC in systemic O transport.
Results: Distinct pools of sAC protein were detected in the RBC cytoplasm, at the plasma membrane and within the nucleus.
iScience
May 2024
Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, 30537 Marburg, Germany.
Popeye domain containing (POPDC) proteins are predominantly expressed in the heart and skeletal muscle, modulating the K potassium channel TREK-1 in a cAMP-dependent manner. and variants cause cardiac conduction disorders with or without muscular dystrophy. Searching for POPDC2-modulated ion channels using a functional co-expression screen in oocytes, we found POPDC proteins to modulate the cardiac sodium channel Nav1.
View Article and Find Full Text PDFGenes (Basel)
February 2024
Department of Physiology & Biophysics, Dalhousie University, Halifax, NS B3H 4R2, Canada.
Popeye domain-containing (POPDC) proteins selectively bind cAMP and mediate cellular responses to sympathetic nervous system (SNS) stimulation. The first discovered human genetic variant () is associated with atrioventricular (AV) block, which is exacerbated by increased SNS activity. Zebrafish carrying the homologous mutation () display a similar phenotype to humans.
View Article and Find Full Text PDFActa Neuropathol Commun
July 2023
National Heart and Lung Institute (NHLI), Imperial College London, London, UK.
Acta Neuropathol Commun
January 2023
National Heart and Lung Institute (NHLI), Imperial College London, London, UK.
The Popeye domain containing (POPDC) genes encode sarcolemma-localized cAMP effector proteins. Mutations in blood vessel epicardial substance (BVES) also known as POPDC1 and POPDC2 have been associated with limb-girdle muscular dystrophy and cardiac arrhythmia. Muscle biopsies of affected patients display impaired membrane trafficking of both POPDC isoforms.
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