Tweety family member 3 (TTYH3)

Tweety family member 3 (TTYH3) is a transmembrane protein and part of the tweety homolog family, which is conserved among eukaryotes. Early experimental studies, patch-clamp assays, and sequence analyses suggested that TTYH3 forms a large conductance, calcium-activated, volume-regulated anion channel (VRAC) involved in responding to cell swelling and regulating chloride/cation homeostasis. However, recent cryo-EM structural data have challenged this view, showing TTYH3 adopts a unique five-transmembrane fold that lacks a canonical ion-conducting pore, and may instead participate in Ca2+-dependent changes in oligomerization, cell adhesion, lipid interaction, and developmental signaling[2][3][5][7]. TTYH3 is highly expressed in excitable and immune tissues (brain, heart, muscle, spleen, etc.), and upregulated in multiple cancers, especially hepatocellular carcinoma (HCC), where its high expression is strongly correlated with poor prognosis and enhanced tumor migration, invasion, EMT, and metastasis[1]. Functional studies suggest TTYH3 acts via interaction with MK5 and GSK3β/β-catenin signaling pathway to promote cancer progression[1]. The protein is being actively investigated as a disease biomarker and possible therapeutic target, although there are no validated drugs or direct targeting agents yet available. Note: TTYH3’s precise molecular function as an ion channel remains disputed. Some structural/functional studies question its role as a pore-forming subunit of chloride channels and suggest non-canonical signaling/adherence roles, while other experiments (especially in cell lines) support its channel function[2][3][5][6][7]. This ongoing controversy means TTYH3 cannot be exclusively classified as a classical “Ion channel” and may need a broader molecular classification if used for structured ontologies.

Other names

Protein tweety homolog 3KIAA1691hTTY3Volume-regulated anion channel subunit TTYH3Tweety homolog 3

Not established in literature. Hypothetically, agents inhibiting TTYH3 could affect chloride/cation flux, EMT, or associated signaling such as MK5/GSK3β/β-catenin pathway. However, direct targeting mechanisms remain speculative.