New Axonemal Dynein Heavy Chains from Tetrahymena thermophila

Abstract

Two dyneins can be extracted from Tetrahymena ciliary axonemes. The 22S dynein contains three heavy chains (HC), sediments at 22S in a sucrose gradient, and makes up the outer arms. The 14S dynein contains two to six HCs, sediments at 14S, and is thought to contribute to formation of the inner arms. We have identified two large proteins that are extracted from Tetrahymena axonemes with high salt and that sediment together at approximately 18S. The two large proteins cleave when subjected to UV light in the presence of ATP and vanadate, suggesting both proteins are dynein HC. Antibodies against one of the 18S HCs do not recognize 22S dynein HCs. Antibodies to 22S dynein HC do not bind appreciably to 18S dynein photocleavage fragments. Taken together, these results indicate that the large proteins that sediment at 18S are axonemal dynein heavy chains.

Disruption of genes encoding predicted inner arm dynein heavy chains causes motility phenotypes in Tetrahymena

“…There are 12 axonemal dynein HC genes found in Tetrahymena [Xu et al, 1999] and 14 in Chlamydomonas . Biochemically, 11 dynein HCs-three outer arm, two I1 inner arm, and six 1-headed inner arm dynein HCshave been resolved from Tetrahymena cilia [Muto et al, 1994;Mobberley et al, 1999;Gibson and Asai, 2000] and Chlamydomonas flagella [Piperno and Luck, 1979;Pfister et al, 1982;Pfister and Witman, 1984;Piperno et al, 1990;Kagami and Kamiya, 1992]. The number of genes generally matches the number of axonemal dynein HCs.…”

“…Eleven different axonemal dynein HCs have been identified in the flagella and cilia of Chlamydomonas and Tetrahymena [Goodenough et al, 1987;Piperno et al, 1990;Kagami and Kamiya, 1992;Gardner et al, 1994;Muto et al, 1994;Mobberley et al, 1999]. Three dynein HCs are found in the outer arm dynein; two form part of the two-headed inner arm dynein (I1) and the other six assemble into 1-headed inner arm dyneins [Piperno and Luck, 1979;Pfister et al, 1982;Pfister and Witman, 1984;Piperno et al, 1990;Kagami and Kamiya, 1992;Muto et al, 1994;Mobberley et al, 1999;Gibson and Asai, 2000].…”

“…Three dynein HCs are found in the outer arm dynein; two form part of the two-headed inner arm dynein (I1) and the other six assemble into 1-headed inner arm dyneins [Piperno and Luck, 1979;Pfister et al, 1982;Pfister and Witman, 1984;Piperno et al, 1990;Kagami and Kamiya, 1992;Muto et al, 1994;Mobberley et al, 1999;Gibson and Asai, 2000].…”

Regulation of monomeric dynein activity by ATP and ADP concentrations

“…The heavy chain of peak-b sometimes separated into two bands, which might indicate the existence of seven heavy chains in 14S dyneins. These possible seven heavy chains of 14S dyneins and two heavy chains sedimented together at 18 S [Mobberley et al, 1999] could explain the nine heavy-chain genes already discovered. The complexity of the inner-arm dyneins in Tetrahymena appears to be similar to that of Chlamydomonas, which is reported to have eight heavy chains [Kagami and Kamiya, 1992].…”

Mutations in genes encoding inner arm dynein heavy chains inTetrahymena thermophila lead to axonemal hypersensitivity to Ca2+

“…Tetrahymena cilia, like most motile cilia and flagella, contain one type of outer arm dynein and at least seven different forms of IADs [Muto et al, 1994;Mobberley et al, 1999;Asai and Wilkes, 2004]. Tetrahymena outer arm dyneins are three-headed motors , while IADs consist of a two-headed dynein called I1 and 6 different one-headed dyneins [Muto et al, 1994;Mobberley et al, 1999;Angus et al, 2001].…”