M3 Muscarinic Receptor Interaction with Phospholipase C beta(3) Determines Its Signaling Efficiency
JOURNAL OF BIOLOGICAL CHEMISTRY
2014; 289 (16): 11206-11218
Purification of Heterotrimeric G Protein alpha Subunits by GST-Ric-8 Association PRIMARY CHARACTERIZATION OF PURIFIED G alpha(olf)
JOURNAL OF BIOLOGICAL CHEMISTRY
2011; 286 (4): 2625-2635
Phospholipase C? (PLC?) enzymes are activated by G protein-coupled receptors through receptor-catalyzed guanine nucleotide exchange on G??? heterotrimers containing Gq family G proteins. Here we report evidence for a direct interaction between M3 muscarinic receptor (M3R) and PLC?3. Both expressed and endogenous M3R interacted with PLC? in coimmunoprecipitation experiments. Stimulation of M3R with carbachol significantly increased this association. Expression of M3R in CHO cells promoted plasma membrane localization of YFP-PLC?3. Deletion of the PLC?3 C terminus or deletion of the PLC?3 PDZ ligand inhibited coimmunoprecipitation with M3R and M3R-dependent PLC?3 plasma membrane localization. Purified PLC?3 bound directly to glutathione S-transferase (GST)-fused M3R intracellular loops 2 and 3 (M3Ri2 and M3Ri3) as well as M3R C terminus (M3R/H8-CT). PLC?3 binding to M3Ri3 was inhibited when the PDZ ligand was removed. In assays using reconstituted purified components in vitro, M3Ri2, M3Ri3, and M3R/H8-CT potentiated G?q-dependent but not G??-dependent PLC?3 activation. Disruption of key residues in M3Ri3N and of the PDZ ligand in PLC?3 inhibited M3Ri3-mediated potentiation. We propose that the M3 muscarinic receptor maximizes the efficiency of PLC?3 signaling beyond its canonical role as a guanine nucleotide exchange factor for G?.
View details for DOI 10.1074/jbc.M113.538546
View details for Web of Science ID 000334638500024
View details for PubMedID 24596086
Phorbol Ester-Induced Podosomes in Normal Human Bronchial Epithelial Cells
JOURNAL OF CELLULAR PHYSIOLOGY
2009; 218 (2): 366-375
Ric-8A and Ric-8B are nonreceptor G protein guanine nucleotide exchange factors that collectively bind the four subfamilies of G protein ? subunits. Co-expression of G? subunits with Ric-8A or Ric-8B in HEK293 cells or insect cells greatly promoted G? protein expression. We exploited these characteristics of Ric-8 proteins to develop a simplified method for recombinant G protein ? subunit purification that was applicable to all G? subunit classes. The method allowed production of the olfactory adenylyl cyclase stimulatory protein G?(olf) for the first time and unprecedented yield of G?(q) and G?(13). G? subunits were co-expressed with GST-tagged Ric-8A or Ric-8B in insect cells. GST-Ric-8·G? complexes were isolated from whole cell detergent lysates with glutathione-Sepharose. G? subunits were dissociated from GST-Ric-8 with GDP-AlF(4)(-) (GTP mimicry) and found to be >80% pure, bind guanosine 5'-[?-thio]triphosphate (GTP?S), and stimulate appropriate G protein effector enzymes. A primary characterization of G?(olf) showed that it binds GTP?S at a rate marginally slower than G?(s short) and directly activates adenylyl cyclase isoforms 3, 5, and 6 with less efficacy than G?(s short).
View details for DOI 10.1074/jbc.M110.178897
View details for Web of Science ID 000286464300028
View details for PubMedID 21115479
Spreading and migration of the basal cells neighboring a wound is essential for airway epithelial repair. To gain insight into the molecular mechanisms that govern these cellular processes, we asked whether normal human airway epithelial cells can form podosomes, a cellular structure discovered from cancer and mesenchymal cells that controls migration and invasion. Herein, we report that phorbol-12, 13-dibutyrate (PDBu), a protein kinase C activator, induced reorganization of cytoskeletal structure in primary normal human bronchial epithelial cells, and in normal human airway epithelial BEAS2B cells. Z-stack scanning confocal microscopy showed that PDBu-induced podosome-like structures contain actin-rich columns that arise from the ventral surface of the cell, and also revealed the presence of circular ruffles/waves at the dorsal cell surface. The molecular components of these cytoskeletal structures were determined with immunofluorescent staining. Using in situ zymography, we demonstrated that PDBu-induced podosomes were capable of degrading fibronectin-gelatin-sucrose matrix. PDBu also increased epithelial cell invasion across Transwell chamber. Podosomes and circular dorsal ruffles may be important for epithelial cell migration and invasion, thus contributing to respiratory epithelial repair and regeneration.
View details for DOI 10.1002/jcp.21609
View details for Web of Science ID 000262270600017
View details for PubMedID 18932175