This proposal remains focused on applications of novel fluorescence methods to measure solute mobility and interactions in living cells and tissues. The central goal of this research is to utilize information about solute dynamics to generate a realistic picture of the intracellular milieu and tissue extracellular spaces that cannot be deduced from static measurements such as electron micrographs. The current proposal utilizes new methodologies (microfiberoptic photobleaching, quantum dot single particle tracking, two-color and polarization fluorescence cross-correlation microscopies) to study molecular diffusion in cell culture and in vivo (mouse) systems.
Aim 1 will measure diffusion in the extracellular space (ECS) of tumor and brain tissues to test the hypothesis that ECS matrix composition and tortuosity restrict macromolecule diffusion. A microfiberoptic epifluorescence photobleaching (MFEP) method will be used to measure diffusion deep in tumor and brain tissue in vivo to quantify the contributions of extracellular matrix composition vs. geometric factors.
Aim 2 will measure plasma membrane diffusion of individual G-protein coupled receptors (GPCRs) to test the hypothesis that cytoskeletal and intrinsic membrane barriers restrict GPCR diffusion. High- resolution tracking of individual, quantum dot (QD)-labeled beta-2 and vasopressin-2 receptors, together with mutagenesis and pharmacological maneuvers, will be used to identify the determinants of receptor diffusion.
Aim 3 will measure protein interactions and rotational dynamics by fluorescence cross-correlation spectroscopy to test the hypotheses that mitochondrial matrix enzymes and membrane CFTR chloride channels form multi-molecular complexes. Following on from extensive preliminary data about the biology of mitochondrial matrix enzymes of the tricarboxylic acid cycle, and CFTR chloride channels, we will use cross- correlation microscopy to define the degree of complexation of mitochondrial matrix enzymes, and role of C- terminus PDZ interactions in restricting CFTR rotational mobility.

National Institute of Health (NIH)
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Method to Extend Research in Time (MERIT) Award (R37)
Project #
Application #
Study Section
Biochemistry and Biophysics of Membranes Study Section (BBM)
Program Officer
Zhang, Yantian
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of California San Francisco
Internal Medicine/Medicine
Schools of Medicine
San Francisco
United States
Zip Code
Son, Jung-Ho; Zhu, Jie S; Phuan, Puay-Wah et al. (2017) High-Potency Phenylquinoxalinone Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Activators. J Med Chem 60:2401-2410
Tradtrantip, Lukmanee; Jin, Bjung-Ju; Yao, Xiaoming et al. (2017) Aquaporin-Targeted Therapeutics: State-of-the-Field. Adv Exp Med Biol 969:239-250
Felix, Christian M; Lee, Sujin; Levin, Marc H et al. (2017) Pro-Secretory Activity and Pharmacology in Rabbits of an Aminophenyl-1,3,5-Triazine CFTR Activator for Dry Eye Disorders. Invest Ophthalmol Vis Sci 58:4506-4513
Lee, Sujin; Phuan, Puay-Wah; Felix, Christian M et al. (2017) Nanomolar-Potency Aminophenyl-1,3,5-triazine Activators of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Chloride Channel for Prosecretory Therapy of Dry Eye Diseases. J Med Chem 60:1210-1218
Verkman, Alan S; Tradtrantip, Lukmanee; Smith, Alex J et al. (2017) Aquaporin Water Channels and Hydrocephalus. Pediatr Neurosurg 52:409-416
Haggie, Peter M; Phuan, Puay-Wah; Tan, Joseph-Anthony et al. (2017) Correctors and Potentiators Rescue Function of the Truncated W1282X-Cystic Fibrosis Transmembrane Regulator (CFTR) Translation Product. J Biol Chem 292:771-785
Cil, Onur; Phuan, Puay-Wah; Son, Jung-Ho et al. (2017) Phenylquinoxalinone CFTR activator as potential prosecretory therapy for constipation. Transl Res 182:14-26.e4
Smith, Alex J; Yao, Xiaoming; Dix, James A et al. (2017) Test of the 'glymphatic' hypothesis demonstrates diffusive and aquaporin-4-independent solute transport in rodent brain parenchyma. Elife 6:
Yao, Xiaoming; Verkman, Alan S (2017) Marked central nervous system pathology in CD59 knockout rats following passive transfer of Neuromyelitis optica immunoglobulin G. Acta Neuropathol Commun 5:15
Jin, Byung-Ju; Verkman, A S (2017) Microfluidic platform for rapid measurement of transepithelial water transport. Lab Chip 17:887-895

Showing the most recent 10 out of 168 publications