The multipurpose 15-protofilament microtubules in C. elegans have specific roles in mechanosensation.
Because microtubules perform many essential functions in neurons, delineating unique roles attributable to these organelles presents a formidable challenge. Microtubules endow neurons with shape and structure and are required for developmental processes including neurite outgrowth, intracellular transport, and synapse formation and plasticity; microtubules in sensory neurons may be required for the above processes in addition to a specific sensory function. In Caenorhabditis elegans, six touch receptor neurons (TRNs) sense gentle touch and uniquely contain 15-protofilament microtubules. Disruption of these microtubules by loss of either the MEC-7 beta-tubulin or MEC-12 alpha-tubulin or by growth in 1 mM colchicine causes touch insensitivity, altered distribution of the touch transduction channel, and a general reduction in protein levels. We show that the effect on touch sensitivity can be separated from the others; microtubule depolymerization in mature TRNs causes touch insensitivity but does not result in protein distribution and production defects. In addition, the mec-12(e1605) mutation selectively causes touch insensitivity without affecting microtubule formation and other cellular processes. Touching e1605 animals produces a reduced mechanoreceptor current that inactivates more rapidly than in wild-type, suggesting a specific role of the microtubules in mechanotransduction.
Bounoutas
Alexander
A
Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
O'Hagan
Robert
R
Chalfie
Martin
M
D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D003078:Colchicine / Q000494:pharmacology; D016695:Glycosyltransferases / Q000172:deficiency / Q000235:genetics; D008465:Mechanoreceptors / Q000502:physiology*; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D008565:Membrane Proteins / Q000032:analysis; D008870:Microtubules / Q000187:drug effects / Q000502:physiology*; D021381:Protein Transport / Q000502:physiology; D014110:Touch / Q000502:physiology*; D014404:Tubulin / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D050257:Tubulin Modulators / Q000494:pharmacology
D029742:Caenorhabditis elegans Proteins; C118234:MEC-12 protein, C elegans; C096705:MEC-2 protein, C elegans; C115872:Mec-7 protein, C elegans; D008565:Membrane Proteins; D014404:Tubulin; D050257:Tubulin Modulators; D016695:Glycosyltransferases; D003078:Colchicine