Fluorescence images were collected using an inverted LSM 710 laser scanning confocal microscope (Zeiss) and Zen 2009 image acquisition software (Zeiss). Individual channels were collected sequentially. Laser lines for excitation were 405 nm, 488 nm and 561 nm, with emissions collected between 440–480, 505–550 and 580–625 nm for blue, green and red fluorescence respectively. Typically, images were collected using a x40 objective with images collected every 1 μm in the z-axis. Global enhancement of brightness and contrast was performed using ZenLite 2011 software (Zeiss).