Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2021 Jan 25;376(1820):20190756. doi: 10.1098/rstb.2019.0756

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© 2021 The Authors.

Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.

PMC Copyright notice

Figure 2. — Excitable networks in chemotaxis and morphogenetic signalling. (a) Activation cycle of small GTPase molecular switches. GTP: guanosine triphosphate; GDP: guanosine diphosphate; GAP: GTPase activating protein; GEF: guanine nucleotide exchange factor. (b) Chemotactic signal processing. See main text for explanation. Protein functions/abbreviations: AdcC: arrestin C; ACA: adenylate cyclase A; CRAC: cytosolic regulator of ACA; cAR1: cAMP receptor; cARppp: C-terminally phosphorylated cAR1; Gα2, β, γ: heterotrimeric G-protein subunits; Ric8: GEF for Gα2; PdsA and RegA: cAMP phosphodiesterases; PdeD: cGMP phosphodiesterase; sGC and GCA: guanylate cyclases; GbpC: cGMP binding protein; Phg2, TorC2, MHCK-A, PKBA, PKBR1, PakA, ERK2 and PKA: protein kinases; PI3K and PI5K: phosphatidyl-inositol kinases; PTEN and Dd5P4: phosphatidyl-inositol phosphatases; ElmoE-Dock: complex with GEF function. Scar: adaptor linking the Arp2/3 actin nucleation complex to Rac; PhdA: actin regulating PH-domain protein. cAMP/cGMP: 3′5′-cyclic adenosine/guanosine monophosphate; 5′AMP/5′GMP: 5′-adenosine/guanosine monophosphate; AbcB3: ABC transporter B3. Violet arrows: cAR1 activated responses that do not require a heterotrimeric G-protein. Blue text and arrows: components of negative feedback loops. (c) Local activation and global inhibition govern actin polymerization. The chemotactic response is best explained by a Turing type reaction–diffusion model. Here stimulation with attractant causes rapidly spreading excitation and more slowly spreading inhibition. At the front of the cell, excitation exceeds inhibition and actin is polymerized, while at the back inhibition is dominant. Redrawn in modified form from [6].