Comparison of hair bundle proteomes from WT and Pls1-knockout mouse utricles
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ABSTRACT: With their stereotyped dimensions and orderly arrangement, as well as their essential role in auditory and vestibular function, stereocilia of sensory hair cells provide a particularly prominent example of the importance of cellular actin protrusions. Uniformity of actin packing in stereocilia is mediated by actin crosslinkers of the plastin, fascin, and espin families. While mice lacking ESPN (espin) have no vestibular function, we found that mice that either lacked PLS1 (plastin 1) or had nonfunctional FSCN2 (fascin 2) had vestibular function that was modestly reduced, with double-mutant mice being more strongly affected. Despite its outsized importance in functional assays, targeted mass spectrometry indicated that ESPN only accounted for ~15% of the total crosslinkers in mouse utricle stereocilia. PLS1 was the most abundant of the crosslinkers, and the second-most-abundant protein overall in stereocilia. Stereocilia lacking PLS1 were shorter and thinner than wild-type stereocilia. Surprisingly, while wild-type stereocilia had random liquid packing of their actin filaments, stereocilia lacking PLS1 had orderly hexagonal packing. Stereocilia with normal PLS1 but that lacked functional FSCN2 had normal liquid packing and normal dimensions. All three crosslinkers are required for normal stereocilia structure and function, but PLS1 biases stereocilia towards liquid packing, which allows stereocilia to grow to greater diameter.
INSTRUMENT(S): LTQ Velos
ORGANISM(S): Mus Musculus (mouse)
TISSUE(S): Utricle, Inner Ear, Vestibular Hair Cell
SUBMITTER: Peter Barr-Gillespie
LAB HEAD: Peter Barr-Gillespie
PROVIDER: PXD004044 | Pride | 2016-09-28
REPOSITORIES: Pride
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