Table 3.

Colocalization of TfR and VAMP-2 with synaptophysin in EE import and export intermediates

	Primary endocytic vesicles				EE-associated tubules/vesicles
Synaptophysin	+	+	−		+	+	−
TfR	+	−	+	n	+	−	+	n
	36  ± 3	39  ± 4	24  ± 3	289	6  ± 2	63  ± 3	31  ± 3	378
Synaptophysin	+	+	−		+	+	−
VAMP-2	+	−	+	n	+	−	+	n
	45  ± 4	38  ± 2	17  ± 2	305	38  ± 3	41  ± 5	21  ± 3	433

Primary endocytic vesicles and EE-associated tubules and vesicles were characterized for their content in double immunogold-labeled sections. Primary endocytic vesicles were defined as ∼85-nm sized and close to the plasma membrane. EE-associated tubules and vesicles were ∼40-nm sized and connected with or at a distance of ≤100 nm from the vacuolar part of EEs. Numbers represent the percentages of total vesicles that contained the indicated proteins and are the means of three counting sessions ± SD.