Capsule polysaccharide is a major virulence factor for a wide range of bacterial pathogens, including Streptococcus pneumoniae. The biosynthesis of Wzy-dependent capsules in both gram-negative and -positive bacteria is regulated by a system involving a protein tyrosine phosphatase (PTP) and a protein tyrosine kinase. However, how the system functions is still controversial. In Streptococcus pne...

Webb, Rachel J., Jacob D. Judah, Lee-Chiang Lo, and Geraint M. H. Thomas. Constitutive secretion of serum albumin requires reversible protein tyrosine phosphorylation events in trans-Golgi. Am J Physiol Cell Physiol 289: C748–C756, 2005. First published April 20, 2005; doi:10.1152/ajpcell.00019.2005.—Serum albumin secretion from rat hepatocytes proceeds via the constitutive pathway. Although mu...

We have used two approaches to identify possible substrates of the insulin receptor (IR) tyrosine kinase. First, we used a potent tyrosine phosphatase inhibitor, phenylarsine oxide (PAO), which is reported to be specific for the insulin-induced signal transduction route, to augment tyrosine phosphorylation. Second, we used src homology 2 (SH2) domains fused to glutathione S-transferase as high ...

A limited collection of signaling networks and transcriptional effectors directs the full spectrum of cellular behaviors that comprise development. One mechanism to diversify regulatory potential is to combine multiple biochemical activities into the same protein. Exemplifying this principle of modularity, Eyes absent (Eya), originally identified as a transcriptional co-activator within the ret...