Chemoattractant receptors activate, recruit and capture G proteins for wide range chemotaxis.

Chemoattractant receptors activate, recruit and capture G proteins for wide range chemotaxis.
Biochem Biophys Res Commun. 2018 Nov 16;:
Authors: Miyanaga Y, Kamimura Y, Kuwayama H, Devreotes PN, Ueda M
Abstract
The wide range sensing of extracellular signals is a common feature of various sensory cells. Eukaryotic chemotactic cells driven by GPCRs and their cognate G proteins are one example. This system endows the cells directional motility towards their destination over long distances. There are several mechanisms to achieve the long dynamic range, including negative regulation of the receptors upon ligand interaction and spatial regulation of G proteins, as we found recently. However, these mechanisms are insufficient to explain the 105-fold range of chemotaxis seen in Dictyostelium. Here, we reveal that the receptor-mediated activation, recruitment, and capturing of G proteins mediate chemotactic signaling at the lower, middle and higher concentration ranges, respectively. These multiple mechanisms of G protein dynamics can successfully cover distinct ranges of ligand concentrations, resulting in seamless and broad chemotaxis. Furthermore, single-molecule imaging analysis showed that the activated Gα subunit forms an unconventional complex with the agonist-bound receptor. This complex formation of GPCR-Gα increased the membrane-binding time of individual Gα molecules and therefore resulted in the local accumulation of Gα. Our...

Source: Biochemical and Biophysical Research communications - November 16, 2018 Category: Biochemistry Authors: Miyanaga Y, Kamimura Y, Kuwayama H, Devreotes PN, Ueda M Tags: Biochem Biophys Res Commun Source Type: research