CELL AND MOLECULAR-BIOLOGY OF FLAGELLAR DYNEINS

This chapter describes some of the unique attributes of flagellar motors and their potential significance for flagellar function, and highlights some structural, enzymatic, and motility properties of flagellar dyneins that may be common to all family members. Many details of dynein structure have been determined, including the sequence of several subunits and the relationship between sequence and quaternary structure. Much of this information can be applied broadly to cytoplasmic as well as flagellar dyneins, and may ultimately provide insights into general motor enzyme mechanisms. Because of their large size, however, dynein genes may yield their secrets more. easily through traditional in uiuo mutagenesis followed by molecular analysis of the most phenotypically interesting mutants, rather than targeted in vitro mutagenesis and transformation. As ATPase enzymes and as molecular motors, dyneins are unique for their large size, variety, and subunit complexity. Genetic and biochemical dissection of flagellar dyneins has revealed that several similar but unique types are present in any given cilium or flagellum, and that some dyneins contain as many as 3 catalytic heavy chains, each greater than 500 kDa, and up to 12 smaller proteins, while others appear to have a single heavy chain and 2 or 3 smaller subunits. © 1994, Academic Press Inc.