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SB401, a pollen‐specific protein from Solanum berthaultii , binds to and bundles microtubules and F‐actin
Author(s) -
Huang Shuli,
Jin Lifeng,
Du Jizhou,
Li Hua,
Zhao Qian,
Ou Guangshuo,
Ao Guangming,
Yuan Ming
Publication year - 2007
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2007.03153.x
Subject(s) - microtubule , negative stain , tubulin , cytoskeleton , actin binding protein , actin , treadmilling , microtubule associated protein , microbiology and biotechnology , biology , biophysics , chemistry , electron microscope , microfilament , actin cytoskeleton , biochemistry , cell , physics , optics
Summary We characterize a novel, pollen‐specific, microtubule‐associated protein, SB401, found in Solanum berthaultii. This protein binds to and bundles taxol‐stabilized microtubules and enhances tubulin polymerization in a concentration‐dependent manner, particularly at lower temperatures. Electron microscopy revealed that the protein decorates the entire length of microtubules. Cross‐linking and electrophoresis studies showed that SB401 protein forms dimers, and suggest that dimerization could account for bundling. Double immunofluorescent staining of pollen tubes of S. berthaultii showed that SB401 protein co‐localized with cortical microtubule bundles. SB401 protein also binds to and bundles actin filaments, and could connect actin filaments to microtubules. SB401 protein had a much higher affinity for microtubules than for actin filaments. In the presence of both cytoskeletal elements, the protein preferentially bound microtubules to form bundles. These results demonstrate that SB401 protein may have important roles in organizing the cytoskeleton in pollen tubes.