Cytoplasmic dynein ATPase activity is regulated by dynactin-dependent phosphorylation

Santosh Kumar, In Hyung Lee, Michael Plamann

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

Cytoplasmic dynein is a microtubule-associated motor that utilizes ATP hydrolysis to conduct minus-end directed transport of various organelles. Dynactin is a multisubunit complex that has been proposed to both link dynein with cargo and activate dynein motor function. The mechanisms by which dynactin regulates dynein activity are not clear. In this study, we examine the role of dynactin in regulating dynein ATPase activity. We show that dynein-microtubule binding and ATP-dependent release of dynein from microtubules are reduced in dynactin null mutants, Δro-3 (p150(Glued)) and Δro-4 (Arp1), relative to wild-type. The dynein-microtubule binding activity, but not the ATP-dependent release of dynein from microtubules, is restored by in vitro mixing of extracts from dynein and dynactin mutants. Dynein produced in a Δro-3 mutant has ~8-fold reduced ATPase activity relative to dynein isolated from wildtype. However, dynein ATPase activity from wild-type is not reduced when dynactin is separated from dynein, suggesting that dynein produced in a dynactin mutant is inactivated. Treatment of dynein isolated from the Δro-3 mutant with λ protein phosphatase restores the ATPase activity to near wild-type levels. The reduced dynein ATPase activity observed in dynactin null murants is mainly due to altered affinity for ATP. Radiolabeling experiments revealed that low molecular mass proteins, particularly 20- and 8-kDa proteins, that immunoprecipitate with dynein heavy chain are hyperphosphorylated in the dynactin mutant and dephosphorylated upon λ protein phosphatase treatment. The results suggest that cytoplasmic dynein ATPase activity is regulated by dynactin-dependent phosphorylation of dynein light chains.

Original languageEnglish (US)
Pages (from-to)31798-31804
Number of pages7
JournalJournal of Biological Chemistry
Volume275
Issue number41
DOIs
StatePublished - Oct 13 2000
Externally publishedYes

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Cytoplasmic Dyneins
Dyneins
Phosphorylation
Microtubules
Adenosine Triphosphate
Dynactin Complex
Phosphoprotein Phosphatases
Adenosine Triphosphatases

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Cytoplasmic dynein ATPase activity is regulated by dynactin-dependent phosphorylation. / Kumar, Santosh; Lee, In Hyung; Plamann, Michael.

In: Journal of Biological Chemistry, Vol. 275, No. 41, 13.10.2000, p. 31798-31804.

Research output: Contribution to journalArticle

Kumar, Santosh ; Lee, In Hyung ; Plamann, Michael. / Cytoplasmic dynein ATPase activity is regulated by dynactin-dependent phosphorylation. In: Journal of Biological Chemistry. 2000 ; Vol. 275, No. 41. pp. 31798-31804.
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