Fig. 2. Translocated 78 kDa flagellar CALK required detergent for solubilization and is present in a more rapidly sedimenting complex in wild-type gametes. (A) 78 kDa CALK translocates into flagella during gamete activation. Cell bodies and flagella isolated from wild-type unactivated mt^– gametes and wild-type mt^– gametes activated by incubation in dibutyryl cAMP were analysed by anti-CALK immunoblotting. (B) Unlike cell body CALK, most translocated 78 kDa flagellar CALK in activated gametes requires detergent to be soluble. The freely soluble, NP-40-soluble (i.e. sedimented at 170,000 g after mechanical disruption and subsequently rendered soluble by addition of NP-40) and NP-40-insoluble fractions of flagella and cell bodies from activated wild-type mt^– gametes were analysed by anti-CALK immunoblotting. (C) Translocated 78 kDa flagellar CALK is part of a higher molecular mass complex. NP-40 extracts, which contained both freely soluble proteins and proteins that required NP-40 to be soluble, were prepared from flagella and cell bodies from activated mt⁺ and mt^– gametes, and fractionated on 5-20% sucrose gradients; the fractions were analysed by anti-CALK immunoblotting.