Cell cycle-dependent phosphorylation of IQGAP is involved in assembly and stability of the contractile ring in fission yeast

Morita, Rikuri; Numata, Osamu; Nakano, Kentaro; Takaine, Masak

doi:10.1016/j.bbrc.2020.10.043

Cited by 7 publications

(7 citation statements)

References 42 publications

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“…We measured a decrease in Cdc12p in the contractile ring of ∼40% of the cells, as reported previously, and a small albeit significant decrease in Rng2p, a protein involved in contractile ring assembly and stability ( Figure 3D ) ( Laporte et al. , 2011 ; Tebbs and Pollard, 2013 ; Morita et al. , 2021 ).…”

Section: Resultssupporting

confidence: 82%

Laser ablation reveals the impact of Cdc15p on the stiffness of the contractile ring

Moshtohry

Bellingham-Johnstun

Elting

et al. 2022

MBoC

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The mechanics that govern the constriction of the contractile ring remain poorly understood yet are critical to understanding the forces that drive cytokinesis. We used laser ablation in fission yeast cells to unravel these mechanics focusing on the role of Cdc15p as a putative anchoring protein. Our work shows that the severed constricting contractile ring recoils to a finite point leaving a gap that can heal if less than ∼1 µm. Severed contractile rings in Cdc15p-depleted cells exhibit an exaggerated recoil, which suggests that the recoil is limited by the anchoring of the ring to the plasma membrane. Based on a physical model of the severed contractile ring, we propose that Cdc15p impacts the stiffness of the contractile ring more than the viscous drag.

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Section: Resultssupporting

confidence: 82%

Laser ablation reveals the impact of Cdc15p on the stiffness of the contractile ring

Moshtohry

Bellingham-Johnstun

Elting

et al. 2022

MBoC

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“…Cdk1 activity inhibits cytokinesis while cells are in mitosis, and multiple cytokinetic proteins are Cdk1 substrates (Wheatley et al, 1997;reviewed in Bohnert and Gould, 2011;Wolf et al, 2007). In S. pombe, Cdk1-mediated phosphorylation of formin Cdc12 (Willet et al, 2018) and IQGAP Rng2 (Morita et al, 2021) antagonizes their CR localization. To test whether this was also the case for Imp2, we endogenously tagged either the Cdk1 site phosphomutants or the CK1 site phosphomutants with sequences encoding mNeonGreen (mNG) (Shaner et al, 2013), combined them with sad1-mCherry to visualize the spindle pole body (SPB) and imaged them at 25°C.…”

Section: Consequences Of Imp2 Phosphorylationmentioning

confidence: 99%

Phosphorylation in the intrinsically disordered region of F-BAR protein Imp2 regulates its contractile ring recruitment

Willet

Igarashi

Chen

et al. 2021

Journal of Cell Science

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The F-BAR protein Imp2 is an important contributor to cytokinesis in the fission yeast, Schizosaccharomyces pombe. Because cell cycle regulated phosphorylation of the central intrinsically disordered region (IDR) of the Imp2 paralog, Cdc15, controls Cdc15 oligomerization state, localization, and ability to bind protein partners, we investigated whether Imp2 is similarly phosphoregulated. We found that Imp2 is endogenously phosphorylated on 28 sites within its IDR with the bulk of phosphorylation being constitutive. In vitro, casein kinase 1 (CK1) Hhp1 and Hhp2 can phosphorylate 17 sites and Cdk1 the remaining 11 sites. Mutations that prevent Cdk1 phosphorylation result in precocious Imp2 recruitment to the cell division site, and mutations designed to mimic these phosphorylation events delay Imp2 CR accumulation. Mutations that eliminated CK1 phosphorylation sites allowed CR sliding, and phosphomimetic substitutions at these sites reduced Imp2 protein levels and slowed CR constriction. Thus, like Cdc15, the Imp2 IDR is phosphorylated at many sites by multiple kinases. In contrast to Cdc15, for which phosphorylation plays a major cell cycle regulatory role, Imp2 phosphorylation is primarily constitutive with milder effects on localization and function.

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“…IQGAP1, the most extensively investigated isoform among IQGAPs, has gained considerable attention since its discovery in 1994 ( 25 ). IQGAP1 is a ubiquitously expressed scaffold protein involved in various vital cellular functions ( 4 , 5 ). IQGAP1 has been postulated to maintain matrix homeostasis via collagen phagocytosis in physiological tissue remodeling ( 26 ).…”

Section: The Isoforms Of Iqgapsmentioning

confidence: 99%

Role of IQ Motif-Containing GTPase-Activating Proteins in Hepatocellular Carcinoma

et al. 2022

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IQ motif-containing GTPase-activating proteins (IQGAPs) are a class of scaffolding proteins, including IQGAP1, IQGAP2, and IQGAP3, which govern multiple cellular activities by facilitating cytoskeletal remodeling and cellular signal transduction. The role of IQGAPs in cancer initiation and progression has received increasing attention in recent years, especially in hepatocellular carcinoma (HCC), where the aberrant expression of IQGAPs is closely related to patient prognosis. IQGAP1 and 3 are upregulated and are considered oncogenes in HCC, while IQGAP2 is downregulated and functions as a tumor suppressor. This review details the three IQGAP isoforms and their respective structures. The expression and role of each protein in different liver diseases and mainly in HCC, as well as the underlying mechanisms, are also presented. This review also provides a reference for further studies on IQGAPs in HCC.

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Cell cycle-dependent phosphorylation of IQGAP is involved in assembly and stability of the contractile ring in fission yeast

Cited by 7 publications

References 42 publications

Laser ablation reveals the impact of Cdc15p on the stiffness of the contractile ring

Laser ablation reveals the impact of Cdc15p on the stiffness of the contractile ring

Phosphorylation in the intrinsically disordered region of F-BAR protein Imp2 regulates its contractile ring recruitment

Role of IQ Motif-Containing GTPase-Activating Proteins in Hepatocellular Carcinoma

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