Talk abstracts
Talk on Thursday 03:00-03:15pm submitted by Aneel Biswas
Hanks-type kinases across all of life and their role in bacterial signal transduction
Aneel N. Biswas (Biophysics Graduate Program), Igor B. Zhulin (Department of Microbiology, The Ohio State University )
Abstract:
Hanks-type protein kinases are extensively studied in eukaryotes and their role is critically important. In contrast, their role in prokaryotes is not understood. Utilizing large, taxonomically diverse protein sequence databases and bioinformatic analysis we identified >800,000 putative kinase sequences and determined their domain architectures and membrane topology. This revealed that membrane-bound kinases are relatively far more common in bacteria than in archaea and eukarya, and bacterial Hanks-type kinases are much more unlikely to have another known signal transduction domain on the same protein than other known bacterial signal transduction domains. To elucidate this observation further, we performed similar analysis to the well-described writer/eraser signaling domain pair GGDEF and EAL, as well as kinases conjugate eraser, protein phosphatases. The number of GGDEF proteins per genome is strongly, linearly correlated to the number of EAL proteins per genome. The relationship between kinases and phosphatases on the other hand is highly lineage-dependent. Surprisingly, unlike kinases, bacterial phosphatase domain architectures are comparable to other bacterial ST-systems. From this and additional evidence, we propose a general mechanism of bacterial kinase signaling where kinases are constitutively active and dephosphorylation is regulated by upstream signals. In addition, this kinase dataset allowed us to infer a phylogenetic history of kinase evolution and describe the distribution of kinases across taxa in unprecedented detail. Taken together our results provide insight into the evolution and role of protein kinases as a signal transduction system.
Keywords: Kinases, Comparative Genomics , Bacterial Signal Transduction