Table 2.

Effect of BFA treatment, endocytic region differences, and internalization protocols on TFR/pIgA-R receptor-ligand clustering

	Basolateral±BFAad		Perinuclear±BFAad		Perinuclear −BFAac vs. +BFAcb		Perinuclear vs. Apical +BFAad
	D/A ≈ 1	D/A ≈ 2	D/A ≈ 1	D/A ≈ 2	D/A ≈ 1	D/A ≈ 2	D/A ≈ 1	D/A ≈ 2
A × variable	p = 9.3 × 10−1 (−)	p = 4.9 × 10−1 (−)	p = 7.1 × 10−1 (−)	p = 7.8 × 10−1 (−)	p = 4.0 × 10−1 (−)	p = 4.2 × 10−2 (−)	p = 4.0 × 10−1 (−)	p = 3.3 × 10−1 (−)
Variable	p = 2.3 × 10−6 (+)	p = 1.3 × 10−9 (+)	p = 3.4 × 10−1 (−)	p = 3.5 × 10−1 (−)	p = 7.0 × 10−3 (−)	p = 3.2 × 10−3 (−)	p = 3.8 × 10−6 (+)	p = 1.7 × 10−5 (+)
Conclusions: effect of BFA on clustering	Increases clustering	Increases clustering	No effect	No effect	No effect and internalization on clustering	No effect and internalization on clustering	Decreased clustering in the apical region	Decreased clustering in the apical region

Endocytic regions: basolateral, perinuclear, and apical; treatments, −BFA and +BFA. A × variable, interaction between A level and variable (i.e., treatment, internalization region, or endocytic region) monitored (test if slopes are identical); Variable, effect of variable in a reduced model where A × variable interaction is removed (test if regression with common slope have the same intercept); p, critical value obtained from an ANCOVA; (+), significant with p < 0.001; (−), not significant.

^a Internalization from basolateral PM.

^b Internalization from opposite PMs.

^c Data from image sets collected with the Bio-Rad confocal microscope (live-cell sample).

^d Data collected with the Nikon confocal microscope (fixed samples).