Characterization of a type I regulatory subunit of cAMP-dependent protein kinase from the bivalve mollusk Mytilus galloprovincialis

2003 ◽  
Vol 416 (1) ◽  
pp. 119-127 ◽  
Author(s):  
Marı́a J. Dı́az-Enrich ◽  
Izaskun Ibarguren ◽  
Ulf Hellman ◽  
J.Antonio Villamarı́n
2001 ◽  
Vol 280 (6) ◽  
pp. L1282-L1289 ◽  
Author(s):  
Stephanie E. Porter ◽  
Lori D. Dwyer-Nield ◽  
Alvin M. Malkinson

Cell shape is mediated in part by the actin cytoskeleton and the actin-binding protein vinculin. These proteins in turn are regulated by protein phosphorylation. We assessed the contribution of cAMP-dependent protein kinase A isozyme I (PKA I) to lung epithelial morphology using the E10/E9 sibling cell lines. PKA I concentration is high in flattened, nontumorigenic E10 cells but low in their round E9 transformants. PKA I activity was lowered in E10 cells by stable transfection with a dominant negative RIα mutant of the PKA I regulatory subunit and was raised in E9 cells by stable transfection with a wild-type Cα catalytic subunit construct. Reciprocal changes in morphology ensued. E10 cells became rounder and grew in colonies, their actin microfilaments were disrupted, and vinculin localization at cell-cell junctions was diminished. The converse occurred in E9 cells on elevating their PKA I content. Demonstration that PKA I is responsible for the dichotomy in these cellular behaviors suggests that manipulating PKA I concentrations in lung cancer would provide useful adjuvant therapy.


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