title: The tubulin deglutamylase CCPP-1 regulates the function and stability of sensory cilia in C. elegans.
abstract: BACKGROUND
  Posttranslational modifications (PTMs) such as acetylation, detyrosination, and polyglutamylation have long been considered markers of stable microtubules and have recently been proposed to guide molecular motors to specific subcellular destinations. Microtubules can be deglutamylated by the cytosolic carboxypeptidase CCP1. Loss of CCP1 in mice causes cerebellar Purkinje cell degeneration. Cilia, which are conserved organelles that play important diverse roles in animal development and sensation, contain axonemes comprising microtubules that are especially prone to PTMs.
  
  
  RESULTS
  Here, we report that a CCP1 homolog, CCPP-1, regulates the ciliary localization of the kinesin-3 KLP-6 and the polycystin PKD-2 in male-specific sensory neurons in C. elegans. In male-specific CEM (cephalic sensilla, male) cilia, ccpp-1 also controls the velocity of the kinesin-2 OSM-3/KIF17 without affecting the transport of kinesin-II cargo. In the core ciliated nervous system of both males and hermaphrodites, loss of ccpp-1 causes progressive defects in amphid and phasmid sensory cilia, suggesting that CCPP-1 activity is required for ciliary maintenance but not ciliogenesis. Affected cilia exhibit defective B-tubules. Loss of TTLL-4, a polyglutamylating enzyme of the tubulin tyrosine ligase-like family, suppresses progressive ciliary defects in ccpp-1 mutants.
  
  
  CONCLUSIONS
  Our studies suggest that CCPP-1 acts as a tubulin deglutamylase that regulates the localization and velocity of kinesin motors and the structural integrity of microtubules in sensory cilia of a multicellular, living animal. We propose that the neuronal degeneration caused by loss of CCP1 in mammals may represent a novel ciliopathy in which cilia are formed but not maintained, depriving the cell of cilia-based signal transduction.
authors: Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
authors: Robert
authors: R
authors: O'Hagan
authors: Brian P
authors: BP
authors: Piasecki
authors: Malan
authors: M
authors: Silva
authors: Prasad
authors: P
authors: Phirke
authors: Ken C Q
authors: KC
authors: Nguyen
authors: David H
authors: DH
authors: Hall
authors: Peter
authors: P
authors: Swoboda
authors: Maureen M
authors: MM
authors: Barr
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002268:Carboxypeptidases / Q000378:metabolism*; D002923:Cilia / Q000000981:diagnostic imaging / Q000378:metabolism; D017124:Conserved Sequence; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D016547:Kinesins / Q000378:metabolism; D008297:Male; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009154:Mutation; D010453:Peptide Synthases / Q000235:genetics / Q000378:metabolism*; D011984:Sensory Receptor Cells / Q000166:cytology* / Q000378:metabolism; D050396:TRPP Cation Channels / Q000235:genetics / Q000378:metabolism; D014404:Tubulin / Q000378:metabolism; D014463:Ultrasonography
chemical_list: D029742:Caenorhabditis elegans Proteins; C093002:OSM-3 protein, C elegans; C527777:PKD-2 protein, C elegans; D050396:TRPP Cation Channels; D014404:Tubulin; C074152:kinesin-II; D049452:Green Fluorescent Proteins; D002268:Carboxypeptidases; C574214:tubulin deglutamylase, C elegans; C500832:KLP-6 protein, C elegans; D016547:Kinesins; D010453:Peptide Synthases; C574215:TTLL-4 protein, C elegans