Table 1.

Movement of TAG-1 beads on the various NrCAM-expressing clones

		Rearward moving			No rearward mobility
		% Escaped initial trap	% Escaped retrapping	% Retrapped	% Escaped retrapping	% Retrapped	(n)	Mean coupling index
	Coupling index	3	2	1	1	0
NrCAM		20	50.8	9	9.2	10	(65)	1.80 ± 0.12
NrCAMΔcyt		17.5	45	7.5	12.5	17.5	(80)	1.56 ± 0.15
NrCAMΔfn		30.6	36.1	5.5	11.7	16.7	(36)	1.88 ± 0.18
NrCAMΔfnΔcyt1a		5	5	15	30	45	(20)	0.78 ± 0.18b
NrCAMΔfnΔcyt2a		1.7	8.3	18.3	23.4	48.3	(60)	0.67 ± 0.13b
NrCAMΔfnΔCter		0	12.5	0	59.4	28.1	(32)	0.84 ± 0.11b
NrCAM/CD		0	4.3	0	73.9	21.7	(23)	0.82 ± 0.10b
NrCAM/MBCD		0	18.7	6.3	62.5	12.5	(16)	1.01 ± 0.14b
NrCAM/DMSO		25	37.5	6.3	18.7	12.5	(16)	1.75 ± 0.25

Initial attachment of beads was induced for a 5-s period with the laser trap in the peripheral region of lamellipodia. Beads that displayed a directional movement toward the proximal region of the lamellipodia (velocity >1 μm/min) were scored as rearward moving. Beads that escaped the trap during the attachment period always displayed a rearward mobility and were scored as “escaped initial trap.” Following the period of trajectory recording, the resistance of beads to displacement with the laser trap was tested: beads were scored as “retrapped” when dragged by the laser trap or as “escaped the trap” when resisting the laser trapping. NrCAM-expressing cells were treated with DMSO, MBCD, or cytochalasin D (CD) for 15 min before laser trapping assays. (n) is the number of beads recorded. For statistical analysis, a coupling index was attributed for each bead behavior as indicated in the table.

^aNrCAMΔfnΔcyt₁ and NrCAMΔfnΔcyt₂ correspond to two clones of stably transfected B104 cells

^bIndicates a significant difference (p<0.01) of the mean coupling index by comparison with full-length NrCAM using ANOVA