Diversity of cilia-based mechanosensory systems and their functions in marine animal behaviour

Abstract

Sensory cells that detect mechanical forces usually have one or more specialized cilia. These mechanosensory cells underlie hearing, proprioception or gravity sensation. To date, it is unclear how cilia contribute to detecting mechanical forces and what is the relationship between mechanosensory ciliated cells in different animal groups and sensory systems. Here, we review examples of ciliated sensory cells with a focus on marine invertebrate animals. We discuss how various ciliated cells mediate mechanosensory responses during feeding, tactic responses or predator–prey interactions. We also highlight some of these systems as interesting and accessible models for future in-depth behavioural, functional and molecular studies. We envisage that embracing a broader diversity of organisms could lead to a more complete view of cilia-based mechanosensation. This article is part of the Theo Murphy meeting issue ‘Unity and diversity of cilia in locomotion and transport’.

Function and Distribution of the Wamide Neuropeptide Superfamily in Metazoans

“…In "GPCR" column, black boxes indicate presence of MIP/sex peptide receptor GPCR ortholog confirmed by receptor deorphanization assay, white boxes indicate currently no orthologous biochemically confirmed GPCR. Phylogeny and presence of genome based on Bezares et al (16), Figure 6, with authors' permission. Tree structure based on a phylogenomic study with Bayesian inference under the CAT + GTR + γ 4 model to suppress long-branch attraction artifacts (17).…”

On the unity and diversity of cilia

“…Similarities between the canonical vertebrate hair cell and the mechanosensory cells of diverse marine invertebrates suggest a common evolutionary origin. Bezares-Calderón et al [67] review and pieces together the often fragmentary literature on the astonishing diversity of mechanosensory cilia in aquatic animals. The authors discuss a rich tapestry of behaviours where ciliary motility and sensing are inextricably coupled, such as in the motor cilia used for swimming and feeding, and in mechanosensory organs necessary for detecting fluid pressures and shear flows.…”

Flagella Ca2+elevations regulate pausing of retrograde intraflagellar transport trains in adherentChlamydomonasflagella

“…Although the repetitive [Ca 2+ ]fla elevations act to prevent the accumulation of paused retrograde IFT trains, in this situation the flagella remain immobilised due to the highly adherent nature of the surface itself. Like many cilia, Chlamydomonas flagella are mechanosensitive and contain a number of candidate ion channels that may contribute to signalling in response to changes in membrane tension 24,44,45 . RNAi knockdown of the transient receptor potential (TRP) channel TRP11 resulted in a defect in the mechanoshock response of swimming Chlamydomonas cells 46 .…”