Using multifocal plane microscopy to reveal novel trafficking processes in the recycling pathway.
A major outstanding issue in cell biology is the lack of understanding of the contribution of tubulovesicular transport carriers (TCs) to intracellular trafficking pathways within 3D cellular environments. This is primarily due to the challenges associated with the use of microscopy techniques to track these highly motile, small compartments. In the present study we have used multifocal plane microscopy with localized photoactivation to overcome these limitations. Using this approach, we have characterized individual components constituting the recycling pathway of the receptor FcRn. Specifically, several different pathways followed by TCs that intersect with larger, relatively static sorting endosomes have been defined. These pathways include a novel 'looping' process in which TCs leave and return to the same sorting endosome. Significantly, TCs with different itineraries can be identified by associations with distinct complements of Rab GTPases, APPL1 and SNX4. These studies provide a framework for further analyses of the recycling pathway.
Department of Immunology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA.
Zhuo
Z
Gan
Sripad
S
Ram
Raimund J
RJ
Ober
E Sally
ES
Ward
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D002460:Cell Line; D011992:Endosomes / Q000378:metabolism; D006801:Humans; D008853:Microscopy / Q000379:methods*; D058305:Sorting Nexins / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000378:metabolism
C464801:APPL1 protein, human; D048868:Adaptor Proteins, Signal Transducing; C513981:SNX4 protein, human; D058305:Sorting Nexins; D020691:rab GTP-Binding Proteins