UBE2O remodels the proteome during terminal erythroid differentiation.

During terminal differentiation, the global protein complement is remodeled, as epitomized by erythrocytes, whose cytosol is ~98% globin. The erythroid proteome undergoes a rapid transition at the reticulocyte stage; however, the mechanisms driving programmed elimination of preexisting cytosolic proteins are unclear. We found that a mutation in the murine gene, which encodes a ubiquitin-conjugating enzyme induced during erythropoiesis, results in anemia.

Quantitative comparison of the fasted and re-fed mouse liver phosphoproteomes using lower pH reductive dimethylation.

Phosphorylation is a common but crucial protein posttranslational modification occurring in virtually all known species. A successful technique for identifying phosphorylation sites is via liquid chromatography-tandem mass spectrometry (LC-MS/MS). In addition to identification, the introduction of stable isotopes allows for LC-MS based quantification of thousands of phosphorylation sites.

A CaMKIIβ signaling pathway at the centrosome regulates dendrite patterning in the brain.

The protein kinase calcium/calmodulin-dependent kinase II (CaMKII) predominantly consists of the α and β isoforms in the brain. Although CaMKIIα functions have been elucidated, the isoform-specific catalytic functions of CaMKIIβ have remained unknown. Using knockdown analyses in primary rat neurons and in the rat cerebellar cortex in vivo, we report that CaMKIIβ operates at the centrosome in a CaMKIIα-independent manner to drive dendrite retraction and pruning.

Phosphoproteome analysis of fission yeast.

Phosphorylation is a key regulator of many events in eukaryotic cells. The acquisition of large-scale phosphorylation data sets from model organisms can pinpoint conserved regulatory inputs and reveal kinase-substrate relationships. Here, we provide the first large-scale phosphorylation analysis of the fission yeast, Schizosaccharomyces pombe.

A functional polymorphism of apolipoprotein C1 detected by mass spectrometry.

A survey of plasma proteins in approximately 1,300 individuals by MALDI-TOF MS resulted in identification of a structural polymorphism of apolipoprotein C1 (ApoC1) that was found only in persons of American Indian or Mexican ancestry. MS/MS analysis revealed that the alteration consisted of a T45S variation. The methyl group of T45 forms part of the lipid-interacting surface of ApoC1.