Translocation of vesicles containing the glucose transporter GLUT4 to the surface of fat and muscle cells is an important part of the body's response to insulin. The signalling pathway involved hinges on phosphoinositide 3-kinase (PI3K) and its downstream kinase PKB (also known as Akt); however, the key PKB targets have remained elusive. Jeremy Tavaré and coworkers now unveil one of these: PIKfyve, an enzyme that generates the phospholipid PtdIns(3,5)P2 from PtdIns(3)P (see ). Identifying PIKfyve as a protein that is phosphorylated in cells stimulated by insulin, the authors show that it is phosphorylated on Ser318 by PKB in vitro and that this increases its activity. They then demonstrate that the PI3K inhibitor wortmannin can block insulin-induced phosphorylation of Ser318 in vivo. Finally, they show that PIKfyve colocalizes with a marker for GLUT4-containing vesicles and can modulate insulin-dependent trafficking of vesicles containing this marker. Their findings thus indicate that PIKfyve is a PKB effector in insulin signalling. However, since it has previously been implicated in endosomal sorting and PKB responds to numerous extracellular stimuli, PIKfyve could have a wider role in signal-regulated membrane trafficking.
Skip Nav Destination
Article navigation
December 2004
Call for papers: Cell Biology of Mitochondria
We are welcoming submissions for our upcoming special issue: Cell Biology of Mitochondria. This issue will be coordinated by two Guest Editors: Ana J. Garcia-Saez (University of Cologne, Germany) and Heidi McBride (McGill University, Canada). Submission deadline: 1 November 2024.
Biologists @ 100 - join us in Liverpool in March 2025
We are excited to invite you to a unique scientific conference, celebrating the 100-year anniversary of The Company of Biologists, and bringing together our different communities. The conference will incorporate the Spring Meetings of the BSCB and the BSDB, the JEB Symposium Sensory Perception in a Changing World and a DMM programme on antimicrobial resistance. Find out more and register your interest to join us in March 2025 in Liverpool, UK.
Intermediate filaments at a glance
Although intermediate filaments are known for their structural support, emerging evidence reveals their involvement in various cellular processes, underscoring their significance in disease development and progression. In this Cell Science at a Glance article, Leila Coelho-Rato and colleagues discuss the established classes of intermediate filaments and their general features, their functions beyond structural support and recent advances in the field.
JCS-FocalPlane Training Grants
Early-career researchers - working in an area covered by JCS - who would like to attend a microscopy training course, please apply. Deadline dates for 2024 applications: 7 September (decision by week commencing 8 October 2024); 22 November (decision by week commencing 16 December).
Immune Cell Interactions in Development, Homeostasis and Immunity
Early-career researchers interested in immune cell interactions, apply now for one of the ten funded places at this Workshop, which will take place 23-26 February 2025. Application deadline: 23 September.
Social media
