GPATCH2

GPATCH2 is a predominantly nuclear G-patch domain protein that acts as a cofactor for the DEAH-box RNA-dependent ATPase hPrp43/DHX15, physically binding the helicase and stimulating its ATPase activity to promote cell growth (PMID:19432882). Beyond this catalytic regulation, GPATCH2 inhibits NF-κB transcriptional activity and restrains G1-S cell cycle progression, with overexpression reducing the S-phase fraction and knockdown enhancing proliferation (PMID:25376275). Its physiological role is constrained by a clean genetic test: deletion in mice yields viable animals with no overt phenotype and no change in basal or induced Tnf expression, arguing against a role as a post-transcriptional repressor of Tnf (PMID:36973252). In hepatocellular carcinoma, GPATCH2 is transcriptionally activated by YY1 and supports proliferation, migration, invasion, and xenograft growth, acting upstream of SNAI2 in an EMT-related program (PMID:41236130).

1. 2009 Medium

   Established the first molecular function of GPATCH2 by identifying a direct binding partner and an enzymatic consequence of that interaction, framing it as a helicase cofactor that drives cell growth.

   Evidence Co-immunoprecipitation and ATPase activity assay with hPrp43/DHX15 plus siRNA knockdown in breast cancer cells

   PMID:19432882

   Open questions at the time

   • No structural basis for the GPATCH2–hPrp43 interaction or the G-patch domain's role in ATPase stimulation
   • RNA substrate or splicing/processing context of the helicase activity not defined
   • Single lab
2. 2014 Medium

   Connected GPATCH2 to transcriptional and cell-cycle control, showing it localizes to the nucleus, suppresses NF-κB activity, and restrains the G1-S transition.

   Evidence EGFP-fusion imaging, NF-κB reporter assay, and CCK-8/colony/flow-cytometry proliferation assays with gain- and loss-of-function in 293T cells

   PMID:25376275

   Open questions at the time

   • Mechanism linking GPATCH2 to NF-κB inhibition not defined
   • Relationship between the helicase cofactor activity and cell-cycle/NF-κB effects unresolved
   • Direct cell-cycle targets unidentified
3. 2023 Medium

   Tested GPATCH2's physiological necessity in vivo and excluded a proposed role as a 3'UTR-mediated post-transcriptional repressor of Tnf.

   Evidence CRISPR Gpatch2 knockout mice with LPS and SMAC-mimetic inflammation models and TNF expression readouts

   PMID:36973252

   Open questions at the time

   • Viability with no overt phenotype leaves the essential in vivo function undefined
   • Testis-enriched expression hints at an unexplored tissue-specific role
   • Possible functional redundancy not addressed
4. 2025 Low

   Placed GPATCH2 in an oncogenic transcriptional circuit, identifying YY1 as an upstream activator and SNAI2/EMT as a downstream effector in hepatocellular carcinoma.

   Evidence siRNA/shRNA loss-of-function in HCC cell lines and xenografts with SNAI2 rescue, EMT marker analysis, and bioinformatic identification of YY1

   PMID:41236130

   Open questions at the time

   • YY1 regulation not confirmed by ChIP or promoter mutagenesis
   • How GPATCH2 mechanistically controls SNAI2 expression is unknown
   • Reconciliation with the earlier anti-proliferative role in 293T cells is unaddressed

• The RNA substrates and biological process served by the GPATCH2–DHX15 helicase complex, and how this connects to its transcriptional and cell-cycle effects, remain undefined.
• No RNA target or processing pathway identified for the GPATCH2/DHX15 module
• No structural model of the complex
• Unifying mechanism linking helicase cofactor, NF-κB inhibition, and cancer growth not established