In proliferating cells, growth and division must be tightly coupled to ensure that cells maintain an appropriate size. However, many of the key proteins that maintain this coordination remain to be identified. On page 2024, Mahasin Osman and colleagues present evidence that IQGAP1 – a Cdc42 effector that has been implicated in human cancer and in exocytosis regulation – integrates cell growth and cell-cycle progression. The authors first show that expression of the C-terminal region of IQGAP1 (IQGAP1-C) promotes the proliferation and migration of cells in culture and reduces cell size. Moreover, they demonstrate that IQGAP1 phosphorylation at a residue in the C-terminus, as well as an interaction between IQGAP1 and Cdc42, are necessary for cell transformation. By contrast, the N-terminal region of IQGAP1 inhibits cytokinesis, increases cell size and impairs transformation and migration. Importantly, the N-terminus of IQGAP1 interacts with mTOR (a key cellular nutrient sensor), and this interaction is necessary for IQGAP1-mediated cell proliferation. The authors propose, therefore, that IQGAP1 acts as a phosphorylation-sensitive switch, and coordinates cell growth and division through its interactions with mTOR and Cdc42, respectively.
Growing and dividing with IQGAP1 Free
Growing and dividing with IQGAP1. J Cell Sci 15 June 2009; 122 (12): e1205. doi:
Download citation file:
Advertisement
Cited by
Interviews with Biologists @ 100 conference speakers

Explore our interviews with keynote speakers from the Biologists @ 100 conference, hosted to celebrate our publisher’s 100th anniversary, where we discuss climate change and biodiversity with Hans-Otto Pörtner and Jane Francis, health and disease with Charles Swanton and Sadaf Farooqi, and emerging technologies with Manu Prakash and Jennifer Lippincott-Schwartz.
Introducing our new Associate Editors

In this Editorial, JCS Editor-in-Chief Michael Way welcomes five new Associate Editors to the JCS team. These Associate Editors will expand our support for the wider cell biology community and handle articles in immune cell biology, proteostasis, imaging and image analysis, plant cell biology, and stem cell biology and modelling.
The spatial choreography of mRNA biosynthesis

In their Review, André Ventura-Gomes and Maria Carmo-Fonseca detail the latest research progress and technological advancements that are helping to unlock how nuclear organisation underpins control of gene transcription and pre-mRNA splicing.
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 2025 applications: 6 June 2025 (decision by week commencing 28 July 2025) and 5 September 2025 (decision by week commencing 20 October 2025).
The emerging roles of the endoplasmic reticulum in mechanosensing and mechanotransduction

In their Review, Jonathan Townson and Cinzia Progida highlight recently emerging evidence for a role of the endoplasmic reticulum in enabling a cell to sense and respond to changes in the extracellular mechanical environment.