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 Feb 4;9:626136. doi: 10.3389/fcell.2021.626136

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

Copyright © 2021 Montaño-Rendón, Grinstein and Walpole.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

PMC Copyright notice

Polarization of phosphoinositide signals during chemotaxis. (A) A representative confocal micrograph of PH-AKT expressed in a RAW264.7 monocytic cell undergoing chemokinesis (random motion) in the presence of growth factors from fetal-bovine serum. PH-AKT bi-specifically recognizes PtdIns(3,4,5)P₃ and PtdIns(3,4)P₂. The image has been pseudocolored to reflect the abundance of the probe. (B) Phosphoinositide signaling controlling “frontness” during leukocyte chemotaxis. A signal arising from the stimulation of cell surface GPCRs and associated activation of G-proteins (β, γ) by chemokines lead to the activation of class I PI3Ks to produce PtdIns(3,4,5)P₃ from PtdIns(4,5)P₂. Together with PtdIns(3,4)P₂, the product of dephosphorylation of PtdIns(3,4,5)P₃, 3-phosphoinositides in the leading-edge membrane mediate a feed-forward loop that activates Rho- and Arf-family GTPases and Lmpd to drive actin polymerization and locally amplify PI3K-signaling. (C) Engagement of substratum by leukocytes favors the “backness” signals PtdIns(4)P and PtdIns(4,5)P₂. PI4KA mediates the synthesis of PtdIns(4)P from PtdIns, which is necessary for the activation of PIP5KIγ90 and the generation of PtdIns(4,5)P₂. RhoA signaling networks and ERM proteins regulated by PtdIns(4,5)P₂ are critical for leukocyte rolling adhesion, diapedesis, and uropod contraction during migration. (D) A representative confocal micrograph of 2xP4M expressed in a RAW264.7 cell undergoing chemokinesis (random motion) in the presence of growth factors from fetal-bovine serum. The P4M domain derived from Legionella's SidM specifically recognizes PtdIns(4)P. The image has been pseudocolored to reflect the abundance of the probe in the Golgi, endolysosomes, and the plasma membrane including in the region of the uropod. GPCR, G protein-coupled receptor; PI3K, phosphoinositide 3-kinase; SHIP, SH2 domain-containing inositol polyphosphate 5-phosphatase; Lmpd, Lamellipodin; ERM, Ezrin-Radixin-Moesin.