title: CLHM-1 is a functionally conserved and conditionally toxic Ca2+-permeable ion channel in Caenorhabditis elegans.
abstract: Disruption of neuronal Ca(2+) homeostasis contributes to neurodegenerative diseases through mechanisms that are not fully understood. A polymorphism in CALHM1, a recently described ion channel that regulates intracellular Ca(2+) levels, is a possible risk factor for late-onset Alzheimer's disease. Since there are six potentially redundant CALHM family members in humans, the physiological and pathophysiological consequences of CALHM1 function in vivo remain unclear. The nematode Caenorhabditis elegans expresses a single CALHM1 homolog, CLHM-1. Here we find that CLHM-1 is expressed at the plasma membrane of sensory neurons and muscles. Like human CALHM1, C. elegans CLHM-1 is a Ca(2+)-permeable ion channel regulated by voltage and extracellular Ca(2+). Loss of clhm-1 in the body-wall muscles disrupts locomotory kinematics and biomechanics, demonstrating that CLHM-1 has a physiologically significant role in vivo. The motility defects observed in clhm-1 mutant animals can be rescued by muscle-specific expression of either C. elegans CLHM-1 or human CALHM1, suggesting that the function of these proteins is conserved in vivo. Overexpression of either C. elegans CLHM-1 or human CALHM1 in neurons is toxic, causing degeneration through a necrotic-like mechanism that is partially Ca(2+) dependent. Our data show that CLHM-1 is a functionally conserved ion channel that plays an important but potentially toxic role in excitable cell function.
authors.affiliation: Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Jessica E
authors.initials: JE
authors.lastname: Tanis
authors.forename: Zhongming
authors.initials: Z
authors.lastname: Ma
authors.forename: Predrag
authors.initials: P
authors.lastname: Krajacic
authors.forename: Liping
authors.initials: L
authors.lastname: He
authors.forename: J Kevin
authors.initials: JK
authors.lastname: Foskett
authors.forename: Todd
authors.initials: T
authors.lastname: Lamitina
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000502:physiology; D029742:Caenorhabditis elegans Proteins / Q000235:genetics* / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000235:genetics* / Q000378:metabolism*; D002462:Cell Membrane / Q000502:physiology; D004558:Electric Stimulation; D006801:Humans; D008124:Locomotion / Q000235:genetics / Q000502:physiology; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D008564:Membrane Potentials / Q000502:physiology; D009410:Nerve Degeneration / Q000473:pathology / Q000503:physiopathology; D009865:Oocytes / Q000166:cytology; D011984:Sensory Receptor Cells / Q000473:pathology / Q000502:physiology; D013045:Species Specificity; D014110:Touch / Q000502:physiology; D019076:Transgenes / Q000235:genetics; D014982:Xenopus laevis
chemical_list: C530077:CALHM1 protein, human; C583793:CLHM-1 protein, C elegans; D029742:Caenorhabditis elegans Proteins; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D008562:Membrane Glycoproteins; D002118:Calcium