title: Chlamydomonas reinhardtii hydin is a central pair protein required for flagellar motility.
abstract: Mutations in Hydin cause hydrocephalus in mice, and HYDIN is a strong candidate for causing hydrocephalus in humans. The gene is conserved in ciliated species, including Chlamydomonas reinhardtii. An antibody raised against C. reinhardtii hydin was specific for an approximately 540-kD flagellar protein that is missing from axonemes of strains that lack the central pair (CP). The antibody specifically decorated the C2 microtubule of the CP apparatus. An 80% knock down of hydin resulted in short flagella lacking the C2b projection of the C2 microtubule; the flagella were arrested at the switch points between the effective and recovery strokes. Biochemical analyses revealed that hydin interacts with the CP proteins CPC1 and kinesin-like protein 1 (KLP1). In conclusion, C. reinhardtii hydin is a CP protein required for flagellar motility and probably involved in the CP-radial spoke control pathway that regulates dynein arm activity. Hydrocephalus caused by mutations in hydin likely involves the malfunctioning of cilia because of a defect in the CP.
authors.affiliation: Department of Cell Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA. karl.lechtreck@umassmed.edu
authors.forename: Karl-Ferdinand
authors.initials: KF
authors.lastname: Lechtreck
authors.forename: George B
authors.initials: GB
authors.lastname: Witman
mesh_terms: D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000378:metabolism* / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000502:physiology; D005407:Flagella / Q000378:metabolism* / Q000648:ultrastructure; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D006849:Hydrocephalus / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D008124:Locomotion / Q000502:physiology*; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D009154:Mutation / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C481382:Hydin protein, mouse; D008840:Microfilament Proteins; D008869:Microtubule-Associated Proteins; D015800:Protozoan Proteins; C087665:kinesin-like protein 1