Cellular functions of cholesterol probed with optical biosensors.
Cholesterol is an essential constituent of cell membranes and the regulation of cholesterol concentration is critical for cell functions including signaling. In this paper, we applied resonant waveguide grating (RWG) biosensor to study the cellular functions of cholesterol through real time monitoring the dynamic mass redistribution (DMR) mediated by cholesterol depletion with methyl-beta-cyclodextrin (mbetaCD). In A431 cells, depletion of cholesterol by mbetaCD led to a DMR signature that was similar, but not identical to that induced by epidermal growth factor (EGF). To elucidate the cellular mechanisms of the DMR signal mediated by cholesterol depletion, a panel of modulators that specifically modulate the activities of various cellular targets were used to pretreat the cells. Results showed that the DMR signals triggered by cholesterol depletion are primarily linked to the transactivation of EGF receptor. Multiple signaling pathways including Ras/mitogenic activated protein (MAP) kinase, protein kinase C (PKC) and phosphatidylinositol 3-kinase (PI3K) acted synergically in the cell response, whereas the activation of protein kinase A (PKA) pathway was found to antagonize the cell response.
Fang
Ye
Y
Biochemical Technologies, Science and Technology Division, Corning Incorporated, Sullivan Park, Corning, NY 14831, USA. fangy2@corning.com
Ferrie
Ann M
AM
Li
Guangshan
G
D015374:Biosensing Techniques; D002118:Calcium / Q000032:analysis; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D002784:Cholesterol / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066246:ErbB Receptors / Q000378:metabolism*; D006801:Humans; D048052:Mitogen-Activated Protein Kinase 3 / Q000032:analysis; D055095:Optics and Photonics; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D015533:Transcriptional Activation; D047392:beta-Cyclodextrins / Q000494:pharmacology; D018631:ras Proteins / Q000378:metabolism
D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D004815:Epidermal Growth Factor; D002784:Cholesterol; D019869:Phosphatidylinositol 3-Kinases; D066246:ErbB Receptors; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D048052:Mitogen-Activated Protein Kinase 3; D018631:ras Proteins; D002118:Calcium