The Saccharomyces cerevisiae Calponin/Transgelin Homolog Scp1 Functions with Fimbrin to Regulate Stability and Organization of the Actin CytoskeletonV
Calponins and transgelins are members of a conserved family of actin-associated proteins widely expressed from yeast to humans. Although a role for calponin in muscle cells has been described, the biochemical activities and in vivo functions of nonmuscle calponins and transgelins are largely unknown...
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Veröffentlicht in: | Molecular biology of the cell 2003-07, Vol.14 (7), p.2617-2629 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Calponins and transgelins are members of a conserved family of
actin-associated proteins widely expressed from yeast to humans. Although a
role for calponin in muscle cells has been described, the biochemical
activities and in vivo functions of nonmuscle calponins and transgelins are
largely unknown. Herein, we have used genetic and biochemical analyses to
characterize the budding yeast member of this family, Scp1, which most closely
resembles transgelin and contains one calponin homology (CH) domain. We show
that Scp1 is a novel component of yeast cortical actin patches and shares in
vivo functions and biochemical activities with Sac6/fimbrin, the one other
actin patch component that contains CH domains. Purified Scp1 binds directly
to filamentous actin, cross-links actin filaments, and stabilizes filaments
against disassembly. Sequences in Scp1 sufficient for actin binding and
cross-linking reside in its carboxy terminus, outside the CH domain.
Overexpression of
SCP1
suppresses
sac6
Δ defects, and
deletion of
SCP1
enhances
sac6
Δ defects. Together,
these data show that Scp1 and Sac6/fimbrin cooperate to stabilize and organize
the yeast actin cytoskeleton. |
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ISSN: | 1059-1524 |
DOI: | 10.1091/mbc.E03-01-0028 |