IGEM:MIT/2005/Overview

Two-Component Signal Transduction - most prokaryotic signal-transduction system and few eukaryotic pathways fall into this category

Basic steps
 * 1) autophosphorylation: HK-His + ATP <=> HK-His-P +ADP
 * 2) phosphotransfer: HK-His-P + RR-Asp <=> HK-His + RR-ASP-P
 * 3) dephosphorylation: RR-Asp-P + H20 <=> RR-Asp + Pi

-Starts with histidine protein kinase (HK) HK sense environmental stimuli and autophosphorylates at it's histidine residue HK has kinase core Environmental stimuli sensing mechnism not very well characterized N-terminal of HK is sensing domain Sensing domain is connected to cytoplasmic kinase core through transmembrane helix and a cytoplasmic linker -HK transfers phosphate to aspartate residue on response regulator (RR) RR catalyzes phosphoryl transfer from HK  Phosphorylation results in confomational change in RR and effects response RR also also catalyze autodephosphoylation RR has 2 domains: N-terminal regulatory domain and a C-terminal effector domain (DNA binding)