Vertebrate and yeast calmodulin, despite significant sequence divergence, are functionally interchangeable.
AUTOR(ES)
Davis, T N
RESUMO
Yeast strains relying solely on vertebrate (Xenopus laevis) calmodulin, expressed under control of a yeast (GAL1) promoter, grew at the same rate as yeast cells containing their endogenous calmodulin. Therefore, the ability to perform essential functions has been conserved between yeast and vertebrate calmodulins, suggesting that calmodulin performs the same (or overlapping) roles in yeast as it does in higher eukaryotes. Successful substitution of vertebrate for yeast calmodulin also suggests that the two proteins can adopt similar conformations in vivo, despite the large number of amino acid differences between them (60 out of 148 residues). Strains overproducing either vertebrate or yeast calmodulin about 100-fold and a strain producing a normal level of yeast calmodulin were essentially indistinguishable in many characteristics, including microtubule distribution, rate of secretion, response to mating pheromone, sporulation, and adaptation to nutrient limitation. Calmodulin overproduction did not confer elevated resistance to a phenothiazine drug, trifluoperazine, thought to be a calmodulin-specific inhibitor. These results have important implications for understanding the role of calmodulin in intracellular calcium signaling.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=298181Documentos Relacionados
- The PARP and rRNA promoters of Trypanosoma brucei are composed of dissimilar sequence elements that are functionally interchangeable.
- The nef gene products of both simian and human immunodeficiency viruses enhance virus infectivity and are functionally interchangeable.
- Gene Loss, Protein Sequence Divergence, Gene Dispensability, Expression Level, and Interactivity Are Correlated in Eukaryotic Evolution
- Are tubulin isotypes functionally significant.
- Human immunodeficiency virus type 1 and type 2 protease monomers are functionally interchangeable in the dimeric enzymes.