Open AccessThe velocity of microtubule sliding: Its stability and load dependency
Author(s) -
Ishijima Sumio
Publication year - 2007
Publication title -
cell motility and the cytoskeleton
Language(s) - English
Resource type - Journals
eISSN - 1097-0169
pISSN - 0886-1544
DOI - 10.1002/cm.20228
Subject(s) - microtubule , biology , flagellum , axoneme , sea urchin , cytoskeleton , biophysics , physics , microbiology and biotechnology , mechanics , anatomy , cell , biochemistry , genetics , gene
It is now well understood that ATP‐driven active sliding between the doublet microtubules in the sperm axoneme generates flagellar movement. However, much remains to be learned about how this movement is controlled. Detailed analyses of the flagellar beating of the mammalian spermatozoa revealed that there were two beating modes at a constant rate of microtubule sliding: that is, a nearly constant‐curvature beating in nonhyperactivated spermatozoa and a nearly constant‐frequency beating in hyperactivated spermatozoa. The constant rate of microtubule sliding suggests that the beat frequency and waveform of the flagellar beating are dependently regulated. Comparison of the sliding velocity of several mammalian and sea urchin sperm flagella with their mechanical property clarified that the sliding velocity of the microtubule was determined by the stiffness of the flagellum at its base, and that its relationship was expressed by a logarithmic equation that is similar to the classical force‐velocity equation of the muscle contraction. Data from sea urchin spermatozoa also satisfied the equation, suggesting that the same microtubule sliding system functions in both the mammalian and echinoderm spermatozoa. Cell Motil. Cytoskeleton 2007. © 2007 Wiley‐Liss, Inc.