GAS2L3

GAS2L3 is a cell-cycle-regulated cytoskeletal crosslinker that acts at the spindle midzone and midbody to ensure faithful chromosome segregation and cytokinetic abscission (PMID:22344256). It directly binds and bundles both microtubules and F-actin in vitro and is transcriptionally controlled as a DREAM complex target, with loss of function producing chromosome segregation defects, multinucleation, and aneuploidy (PMID:22344256). Its mitotic abundance is tightly timed: GAS2L3 is phosphorylated by Cdk1 in mitosis and targeted for degradation by APC/C(Cdh1) but not APC/C(Cdc20), and late in cytokinesis it concentrates at constriction sites of the intercellular bridge, where overexpression blocks abscission (PMID:23469016). GAS2L3 functions as a downstream effector of the chromosomal passenger complex, its conserved GAR domain binding the borealin C-terminus and survivin N-terminus, an interaction required for recruitment to the constriction zone (PMID:24571573). At the midbody it drives abscission by forming intrinsically disordered region (IDR)-dependent liquid-liquid phase separation condensates that scaffold CHMP4B condensate assembly; IDR deletion or knockdown causes defective cytokinesis and G1 arrest (PMID:41177429). In vivo, GAS2L3 deficiency causes premature cardiomyocyte binucleation from incomplete cytokinesis, unresolved midbodies, and a p53/p21 program, leading to neonatal heart failure in knockout mice (PMID:28698371), and is required for normal brain morphogenesis and cell proliferation in zebrafish (PMID:25131197).

1. 2012 High

   Established GAS2L3 as a DREAM-controlled midzone/midbody protein whose loss disrupts genome stability, defining its core role in mitosis and cytokinesis.

   Evidence RNAi knockdown with live imaging, in vitro microtubule/actin bundling assays, and immunofluorescence localization

   PMID:22344256

   Open questions at the time

   • Does not resolve how GAS2L3 is recruited to the midbody
   • Molecular partners at the midzone not identified
2. 2012 Low

   Placed GAS2L3 downstream of necdin in a hematopoietic stem cell genotoxic stress response, hinting at a role beyond cell-cycle mechanics.

   Evidence Genetic epistasis using necdin-null HSC transplantation with irradiation/chemotherapy challenge

   PMID:22776820

   Open questions at the time

   • GAS2L3-specific molecular mechanism not directly dissected
   • Inferred by epistasis in a single study
   • Link to its mitotic function unclear
3. 2013 High

   Defined how GAS2L3 abundance is timed across the cell cycle, showing it is a Cdk1 substrate and an APC/C(Cdh1)-specific degradation target, and that its levels must be controlled for abscission to proceed.

   Evidence Cell-free ubiquitination assays in frog egg and human extracts, Cdk1 phosphorylation assay, and overexpression abscission assay

   PMID:23469016

   Open questions at the time

   • Cdk1 phosphosites and their functional consequence not mapped
   • How degradation timing couples to abscission completion unresolved
4. 2014 High

   Identified the GAR domain as the CPC-binding module linking GAS2L3 to borealin and survivin, establishing it as a CPC effector recruited to the constriction zone.

   Evidence Pulldown/co-IP with CPC subunits, domain deletion/mutagenesis, and immunofluorescence localization

   PMID:24571573

   Open questions at the time

   • Reciprocal validation and structural detail of the GAR-borealin/survivin interface not provided
   • How CPC binding triggers downstream abscission events unknown
5. 2014 Medium

   Distinguished GAS2L3 from its paralogs G2L1/G2L2, showing it localizes to actin and microtubules but lacks EB-dependent microtubule-stabilizing activity, refining its functional niche.

   Evidence Fluorescence microscopy, live-cell imaging, and biochemical analysis of EB protein binding

   PMID:24706950

   Open questions at the time

   • GAS2L3-specific finding is largely negative
   • Single-lab data on functional distinction from paralogs
6. 2014 Medium

   Demonstrated an in vivo developmental requirement for Gas2l3 in zebrafish brain morphogenesis and proliferation, confirmed by mRNA rescue.

   Evidence Morpholino knockdown with mRNA rescue and histological analysis in zebrafish

   PMID:25131197

   Open questions at the time

   • Mechanistic depth limited
   • Whether the phenotype is purely cytokinesis-driven not established
7. 2017 High

   Provided definitive in vivo evidence that GAS2L3 cytokinesis function is essential in the heart, linking its loss to cardiomyocyte binucleation, a p53/p21 program, and neonatal lethality.

   Evidence Constitutive and cardiomyocyte-specific knockout mice with histology, immunofluorescence, and gene expression analysis

   PMID:28698371

   Open questions at the time

   • Mechanism connecting failed abscission to p53 activation not detailed
   • Tissue-selective vulnerability of cardiomyocytes unexplained
8. 2025 High

   Revealed the biophysical mechanism of GAS2L3 at the midbody — IDR-driven phase separation that scaffolds CHMP4B condensates to accelerate abscission — and tied it to tumorigenicity.

   Evidence FRAP, in vitro droplet assays, IDR-deletion constructs, and knockdown with cytokinesis/cell-cycle readouts in HCC cells

   PMID:41177429

   Open questions at the time

   • Single lab
   • How IDR condensates physically promote CHMP4B/ESCRT polymerization not resolved
   • Relationship between LLPS and the GAR-CPC recruitment pathway unclear
9. 2025 Medium

   Extended GAS2L3 beyond intracellular mitosis to an exosomal role promoting cancer-associated fibroblast migration and recruitment.

   Evidence Exosome proteomics and GAS2L3 loss-of-function fibroblast migration assays

   PMID:40664041

   Open questions at the time

   • Limited mechanistic depth
   • How a cytoskeletal/midbody protein acts extracellularly is unexplained

• How the cell-cycle regulation (Cdk1/APC-Cdh1), CPC recruitment, and IDR-based phase separation are integrated into a single abscission program, and how this connects to the p53 stress responses seen in vivo, remains unresolved.
• No unified model linking degradation timing, CPC binding, and condensate formation
• Mechanism coupling failed cytokinesis to p53/p21 activation undefined