Table 2.

Morphological changes in EEs after transfection of PC12 cells with wild type rab4, Q67Lrab4, and S22Nrab4

	No. of EE-associated vesicles	Membrane length (nm)
		EE vacuole	EE tubules
Endogenous rab4	6.8  ± 0.6	1410  ± 38	142  ± 23
Wild-type rab4	9.1  ± 0.7	618  ± 27	379  ± 45
Q67Lrab4	13.5  ± 1.0	619  ± 28	181  ± 19
S22Nrab4	4.4  ± 0.6	940  ± 36	508  ± 37

The average number of vesicles (± SEM) associated with an EE was determined by counting all vesicular profiles within 100 nm of an EE vacuole of which the length was less than twice the diameter. The average membrane length ± SEM of EE vacuoles and tubules was established by counting the number of intersections with a lattice overlay. Only tubules that were visibly connected to the EE vacuolar domain were taken into account. Countings were done on 30 EEs (defined as in de Wit et al., 1999) of each cell line.