Impact of actin rearrangement and degranulation on the membrane structure of primary mast cells: a combined atomic force and laser scanning confocal microscopy investigation.
Degranulation of bone marrow-derived mast cells (BMMCs) triggered by antigens (e.g., 2,4-dinitrophenylated bovine serum albumin (DNP-BSA) and secretagogues (e.g., poly-L-lysine) was investigated by combined atomic force microscopy (AFM) and laser scanning confocal microscopy (LSCM). This combination enables the simultaneous visualization and correlation of membrane morphology with cytoskeletal actin arrangement and intracellular granules. Two degranulation mechanisms and detailed membrane structures that directly corresponded to the two stimuli were revealed. In DNP-BSA triggered activation, characteristic membrane ridges formed in accordance with the rearrangement of underlying F-actin networks. Individual granules were visualized after they released their contents, indicating a "kiss-and-run" pathway. In BMMCs stimulated by poly-L-lysine, lamellopodia and filopodia were observed in association with the F-actin assemblies at and near the cell periphery, whereas craters were observed on the central membrane lacking F-actin. These craters represent a new membrane feature resulting from the "kiss-and-merge" granule fusion. This work provides what we believe is important new insight into the local membrane structures in correlation with the cytoskeleton arrangement and detailed degranulation processes.
Deng
Zhao
Z
Department of Chemistry, University of California, Davis, California, USA.
Zink
Tiffany
T
Chen
Huan-yuan
HY
Walters
Deron
D
Liu
Fu-tong
FT
Liu
Gang-yu
GY
D008841:Actin Cytoskeleton / Q000648:ultrastructure*; D000199:Actins / Q000378:metabolism*; D000818:Animals; D015550:Cell Degranulation / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D004140:Dinitrophenols / Q000494:pharmacology; D008407:Mast Cells / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D051379:Mice; D008810:Mice, Inbred C57BL; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D011107:Polylysine / Q000494:pharmacology; D011554:Pseudopodia / Q000378:metabolism / Q000648:ultrastructure; D012710:Serum Albumin, Bovine / Q000494:pharmacology
D000199:Actins; D004140:Dinitrophenols; C034638:dinitrophenyl-bovine serum albumin; D011107:Polylysine; D012710:Serum Albumin, Bovine