Table I. The percentage of cells displaying similar immunofluorescence patterns after incubation with various extraction buffers and staining with vimentin and dynein antibodies.

	No NaCl added			No NaCl added			1 M NaCl
	Average	SD	N	Average	SD	N	Average	SD	N
	%			%			%
Digitonin
0.1%	16	±3	147	16	±7	200	11	±4	183
0.5%	24	±11	129	22	±11	100	13	±6	160
1.0%	34	±15	151	32	±1	100	12	±3	186
NP-40
0.1%	43	±10	200	31	±15	150	41	±1	150
0.5%	67	±16	100	80	±12	175	74	±20	300
1.0%	73	±9	113	62	±3	100	83	±9	130
Triton X-100
0.1%	59	±12	180	37	±4	200	46	±8	220
0.5%	64	±6	134	88	±6	200	92	±3	100
1.0%	90	±11	100	66	±1	180	81	±18	100
IF prep				98	±1	250

To determine the extent of association among vimentin, dynein, and dynactin, BHK-21 cells were incubated with various extraction solutions before fixation. All extraction solutions contained 100 mM Hepes, pH 7.4, 60 mM Pipes, and protease inhibitors (see Materials and methods). In addition, solutions contained either 0.1, 0.5, or 1.0% digitonin, NP-40, or Triton X-100 and either 0.5 M,1 M, or no NaCl. The “IF prep” extraction buffer contained 1% Triton X-100, 1 mg/ml DNase 1, and 0.5 M NaCl (see Materials and methods). In all cases, data was pooled from three different experiments for each detergent and each salt concentration. The average percentage of cells displaying similar patterns between vimentin and dynein HC are represented in the table.