Fig. 1. Inactivation of ERM proteins in L cells by microinjection of C3
transferase. (A-C) Rh-dextran and C3 transferase were co-microinjected into L
cells. After a 30 minute incubation, cells were fixed with TCA/formaldehyde,
and microinjected cells were identified by the fluorescence of Rh-dextran (A).
Cells were then doubly stained with anti-ERM mAb, CR22 (B) and anti-CPERM mAb
(C). C3 induced dephosphorylation of CPERMs (C), with concomitant
translocation of ERM proteins from microvilli to the cytoplasm (B). (D-G) L
cells grown on CELLocateTM coverslips were microinjected with
C3/F-dextran followed by glutaraldehyde fixation. Their phase-contrast (D) and
fluorescence (E) images were recorded to identify microinjected cells.
Scanning electron microscopy showed that a non-microinjected cell (arrowheads)
bore numerous microvilli on its surface (F), whereas a microinjected cell
(arrow) was characterized by a smooth cell surface (G). Bars, A-C, 10 µm;
D, E, 10 µm; F, G, 2 µm.
