SNX11

SNX11 is an endosomal sorting nexin that regulates endolysosomal membrane homeostasis and the surface levels of plasma-membrane cargo through a structurally distinct lipid- and protein-binding module (PMID:23615901, PMID:26818531). Its defining feature is an extended PX (PXe) domain in which two C-terminal α-helices augment the canonical PX fold and are indispensable for SNX11 function, including suppression of SNX10-induced vacuolation (PMID:23615901); this domain binds PI(3,5)P2, establishing SNX11 as a phosphoinositide effector on endosomal membranes (PMID:32561432). SNX11 couples this lipid recognition to the vacuolar H+-ATPase by interacting with the V1 subunit, controlling V-ATPase assembly and thereby endosomal pH (PMID:32561432, PMID:40732723). Functionally, SNX11 directs cargo toward lysosomal degradation: it binds the thermosensor TRPV3 and routes it from the plasma membrane to lysosomes, lowering TRPV3 surface levels and current, so that loss of SNX11 elevates TRPV3 and sharpens thermal perception in vivo (PMID:26818531, PMID:31730264). SNX11 is also a required component of a microtubule-dependent pathway that translocates the GPCR F2rl1 (PAR2) from the plasma membrane to the nucleus, where PAR2 recruits Sp1 to the Vegfa promoter to drive neovascularization (PMID:25216639). Through its control of endosomal pH and V-ATPase function, SNX11 acts as an essential host factor that multiple enveloped viruses exploit for endolysosomal escape (PMID:31215001, PMID:40732723).

1. 2013 High

   Defined the structural basis of SNX11 by revealing an extended PX (PXe) domain, answering whether SNX11 is a conventional PX-domain protein and which features carry its activity.

   Evidence X-ray crystallography of truncated human SNX11 with structure-guided mutagenesis and an in vitro vacuolation assay

   PMID:23615901

   Open questions at the time

   • Did not identify the physiological lipid ligand
   • No full-length structure or membrane-bound conformation
   • Cellular role beyond SNX10-vacuolation suppression not addressed
2. 2014 Medium

   Placed SNX11 in a nuclear-trafficking pathway for a GPCR, showing it is required to shuttle F2rl1/PAR2 to the nucleus to activate Vegfa transcription and angiogenesis.

   Evidence Live-cell imaging, subcellular fractionation, loss-of-function, and in vivo retinal vascular assays

   PMID:25216639

   Open questions at the time

   • SNX11-specific molecular mechanism within the shuttle not resolved
   • Direct SNX11–PAR2 interaction not established
   • Single-lab finding
3. 2016 High

   Established SNX11 as a degradative sorting factor by identifying TRPV3 as cargo it routes from the plasma membrane to lysosomes, linking SNX11 to control of an ion channel's surface abundance.

   Evidence Co-IP, colocalization/fractionation, OE and siRNA knockdown, patch-clamp, and lysosomal inhibitor rescue in HEK293T and HaCaT cells

   PMID:26818531

   Open questions at the time

   • Did not define the recognition motif on TRPV3
   • Lysosomal targeting machinery downstream of SNX11 unspecified
   • Generality across other channel cargo unknown
4. 2019 High

   Demonstrated the in vivo physiological consequence of SNX11-mediated TRPV3 control, showing it tunes thermal perception in the whole animal.

   Evidence Snx11 germline knockout mice with thermal behavioural assays, plus keratinocyte patch-clamp and protein quantification

   PMID:31730264

   Open questions at the time

   • Tissue-specific contributions not dissected
   • Whether other thermosensors are co-regulated unknown
5. 2019 Medium

   Identified SNX11 as an essential host factor for viral infection, connecting its endosomal role to endolysosomal escape of an enveloped virus.

   Evidence Genome-wide CRISPR-Cas9 screen, SNX11-KO HeLa cells, viral replication and glycoprotein localization assays, endosomal pH and LAMP1 measurement

   PMID:31215001

   Open questions at the time

   • Molecular basis of the pH/escape defect not mechanistically resolved at this stage
   • Single virus tested
   • Single-lab study
6. 2020 High

   Defined SNX11 as a PI(3,5)P2 effector and linked its lipid binding to V-ATPase, providing a mechanistic bridge from phosphoinositide signaling to endosome homeostasis.

   Evidence Crystal structures of PI(3,5)P2-bound and apo SNX11, Co-IP with V-ATPase V1D subunit, and molecular dynamics simulations

   PMID:32561432

   Open questions at the time

   • Functional consequence of V-ATPase binding not tested in cells here
   • α5 helix unfolding upon membrane targeting inferred from simulation, not measured
   • Direct binding to V-ATPase not validated reciprocally in vivo
7. 2025 Medium

   Unified the endosomal and antiviral roles by showing SNX11 controls V-ATPase assembly and endosomal pH, explaining how its loss blocks escape of multiple enveloped viruses.

   Evidence Co-IP with V-ATPase V1 subunit, SNX11-KO cell lines, endosomal pH measurement, V-ATPase subunit western blots, and replication assays for SFTSV, dengue, hantavirus, and influenza

   PMID:40732723

   Open questions at the time

   • Stoichiometry and structural basis of the SNX11–V1 interaction not resolved
   • How PI(3,5)P2 binding and V-ATPase regulation are mechanistically coupled unclear
   • Single-lab study

• How SNX11's PI(3,5)P2 binding, V-ATPase regulation, and selective cargo recognition are mechanistically integrated into one degradative/sorting machine remains unresolved.
• No defined cargo-recognition determinant linking lipid binding to substrate selection
• No full-length membrane-bound structural model
• Relationship between nuclear GPCR trafficking and endosomal V-ATPase roles unexplained