title: Automatically Identifying Fusion Events between GLUT4 Storage Vesicles and the Plasma Membrane in TIRF Microscopy Image Sequences.
abstract: Quantitative analysis of the dynamic behavior about membrane-bound secretory vesicles has proven to be important in biological research. This paper proposes a novel approach to automatically identify the elusive fusion events between VAMP2-pHluorin labeled GLUT4 storage vesicles (GSVs) and the plasma membrane. The differentiation is implemented to detect the initiation of fusion events by modified forward subtraction of consecutive frames in the TIRFM image sequence. Spatially connected pixels in difference images brighter than a specified adaptive threshold are grouped into a distinct fusion spot. The vesicles are located at the intensity-weighted centroid of their fusion spots. To reveal the true in vivo nature of a fusion event, 2D Gaussian fitting for the fusion spot is used to derive the intensity-weighted centroid and the spot size during the fusion process. The fusion event and its termination can be determined according to the change of spot size. The method is evaluated on real experiment data with ground truth annotated by expert cell biologists. The evaluation results show that it can achieve relatively high accuracy comparing favorably to the manual analysis, yet at a small fraction of time.
authors.affiliation: Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China ; Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Hangzhou 310027, China ; Key Laboratory for Biomedical Engineering of Ministry of Education, Hangzhou 310027, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China ; Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Hangzhou 310027, China ; Key Laboratory for Biomedical Engineering of Ministry of Education, Hangzhou 310027, China.
authors.forename: Yingke
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China ; Key Laboratory for Biomedical Engineering of Ministry of Education, Hangzhou 310027, China.
authors.forename: Zhouyan
authors.initials: Z
authors.lastname: Feng
authors.affiliation: Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310027, China ; Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Hangzhou 310027, China ; Key Laboratory for Biomedical Engineering of Ministry of Education, Hangzhou 310027, China ; Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou 310027, China.
authors.forename: Xiaoxiang
authors.initials: X
authors.lastname: Zheng
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D019295:Computational Biology; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D008561:Membrane Fusion / Q000502:physiology*; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods; D022142:Secretory Vesicles / Q000378:metabolism; D050988:Vesicle-Associated Membrane Protein 2 / Q000378:metabolism
chemical_list: D051275:Glucose Transporter Type 4; C485187:PHluorin; C495693:Slc2a4 protein, mouse; D050988:Vesicle-Associated Membrane Protein 2; C494808:vesicle-associated membrane protein 2, mouse; D049452:Green Fluorescent Proteins