Monday, August 16, 2010

Update of the week (16-22 august)

New Review in "Nature Reviews Molecular Cell Biology" (Impact Factor - 42)
Molecular mechanisms of organelle inheritance: lessons from peroxisomes in yeast
Andrei Fagarasanu, Fred D. Mast, Barbara Knoblach, Richard A. Rachubinski

New biophysical Paper in Biochimie (Impact factor 3.9)
Human liver peroxisomal alanine:Glyoxylate aminotransferase: Different stability under chemical stress of the major allele, the minor allele, and its pathogenic G170R variant

New Clinical Article in Cardiovascular Pathology
Targeted intracellular catalase delivery protects neonatal rat myocytes from hypoxia-reoxygenation and ischemia-reperfusion injury
Authors tested whether SKL-tagget catalase increases the intracellular levels of the antioxidant enzyme catalase in neonatal rat ventricular myocytes and whether catalase-SKL imparts protection against hypoxia–reoxygenation and ischemia reperfusion injury.

Brief intro - in humans, catalase is a PTS1 bearing protein but the PTS1 is quite unique and differs from the consensus SKL. The last four residues of catalase KANL constitute the PTS1 where aspargine and Lysine both are necessary and essential for PTS1 function. catalase PTS1 is not as efficient as other PTS1 signals. Why did cell chose such PTS1, instead of SKL??

There is another recent paper "A Proteome-Wide Perspective on Peroxisome Targeting Signal 1(PTS1)-Pex5p Affinities". The authors experimentally determined the affinity of Pex5 for different PTS1 containing peptides. They observed that Catalse PTS1 has substantially lower affinity towards the pex5 (PTS1 receptor ) than other PTS1 sequences. To account for this disparity, the plausible explanation is the levels of expression, where high affinity PTS1 proteins are less expressed in cell while low affinity PTS1 proteins like catalse are expressed at higher levels.

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