Pesquisa com proteínas mostra elo evolucionário entre plantas e humanos

segunda-feira, fevereiro 22, 2010

"Você é um banana!", "Ele é laranja de eminente político em Brasília", "Ela é uma uva, um xuxuzinho", "Ficou velho com cara de genipapo". Essas, entre outras, expressões em português em que o ser humano é comparado a uma dessas frutas parece ganhar mais força devido à uma pesquisa científica que mostra este grau de relação evolutiva. Nós somos 55% semelhantes a bananas, QED, um de nossos ancestrais foi um banana!!! E assim vai a Lógica Darwiniana 101.


Protein Study Shows Evolutionary Link Between Plants, Humans

ScienceDaily (Feb. 15, 2010) — Inserting a human protein important in cancer development was able to revive dying plants, showing an evolutionary link between plants and humans and possibly making it easier to study the protein's function in cancer development, a Purdue University study has shown.

Scientist holding the model plant Arabidopsis in the laboratory. (Credit: iStockphoto)

The aminopeptidase M1 protein, or APM1, is critical for root development in plants. Arabidopsis plants lacking the protein will die, but can be rescued if the protein is restored.

During experiments, Wendy Peer, a research assistant professor of horticulture, found that inserting a similar protein found in humans, called insulin responsive aminopeptidase, or IRAP, also rescued the plants.

"APM1 and IRAP are in the same group," said Peer, whose results were published in the early online version of the journal Plant Physiology. "M1 aminopeptidase activity is such a fundamental process that it's been conserved evolutionarily. This protein has changed very little over time."

Peer said the finding could advance the understanding of this class of proteins because it might make it possible to conduct studies with plants instead of animals, offering researchers more control and options. Humans with altered function of the equivalent proteins often have leukemia or other cancers.
Read more here/Leia mais aqui: Science Daily


Plant Physiology Preview
Published on February 12, 2010; 10.1104/pp.109.148742

Received October 2, 2009
Accepted February 3, 2010

The catalytic and protein-protein interaction domains are required for APM1 functionFazeeda N. Hosein , Anindita Bandyopadhyay , Wendy Ann Peer *, and Angus S. Murphy

Department of Horticulture, Purdue University, West Lafayette, IN 47907

* Corresponding author; email:

The M1 metallopeptidase APM1 is essential for embryonic, vegetative, and reproductive development in Arabidopsis. Here we show that, like mammalian M1 proteases, APM1 appears to have distinct enzymatic and protein-protein interaction domains and functions as a homodimer. Arabidopsis seedlings treated with ezetimibe, an inhibitor of M1 protein-protein interactions, mimicked a subset of apm1phenotypes distinct from those resulting from treatment with PAQ-22, an inhibitor of M1 catalytic activity, suggesting that the APM1 catalytic and interaction domains can function independently. apm1-1 knockdown mutants transformed with catalytically inactive APM1 did not prevent seedling lethality. However, apm1-2 has a functional enzymatic domain but lacks the C-terminus, and transformation with catalytically inactive APM1 rescued the mutant. Overexpression of human IRAP rescued all apm1phenotypes, suggesting that the catalytic activity was sufficient to compensate for loss of APM1 function, while overexpression of catalytically inactive IRAP only rescued apm1-2. Increased catalytic activity alone is not sufficient to compensate for loss-of-APM1-function, as overexpression of another Arabidopsis M1 family member lacking an extended C-terminus did not rescue apm1-1. The protein interactions facilitating enzymatic activity appear to be dependent on the C-terminus of APM1, as transformation with an open reading frame containing an internal deletion of a portion of the C-terminus or a point mutation in a dileucine motif did not rescue the mutant. These results suggest that both the catalytic and interaction domains are necessary for APM1 function, but that APM1 function and dimerization does not require these domains to be present in the same linear molecule.