ADAM11

ADAM11 is a catalytically inactive, brain-enriched member of the ADAM (a disintegrin and metalloproteinase) family that functions as a transmembrane adhesion and scaffolding molecule in the nervous system. Its metalloprotease-like domain lacks a functional zinc-binding motif, and its disintegrin domain lacks the canonical RGD integrin-binding sequence, consistent with non-proteolytic roles in cell–cell interaction (PMID:9693107). ADAM11 serves as a receptor for the secreted ligands LGI1 and LGI4 (PMID:18974846) and is essential for anchoring Kv1.1/Kv1.2 potassium channel complexes at the cerebellar basket cell pinceau terminal, where these channels mediate ultrarapid ephaptic (non-synaptic electrical) inhibition of Purkinje cell firing (PMID:26269648). Loss of ADAM11 in mice impairs spatial learning, motor coordination, and inflammatory nociception (PMID:16504143, PMID:16729981).

1. 1993 Medium

   Identification of ADAM11 as a novel metalloprotease-disintegrin-cysteine-rich gene at 17q21.3 established it as a candidate of interest, initially through somatic rearrangements in breast tumors.

   Evidence Genomic cloning from a cosmid library with Southern blot detection of rearrangements in primary breast cancers

   PMID:8252040

   Open questions at the time

   • Tumor-suppressor role never independently validated
   • No functional assay performed
   • Only two tumors showed rearrangement
2. 1998 Medium

   Sequence analysis resolved that ADAM11 is catalytically inactive due to a disrupted zinc-binding motif and lacks the RGD disintegrin sequence, redirecting its functional interpretation from a protease toward an adhesion/scaffolding molecule.

   Evidence cDNA cloning and sequence comparison of metalloprotease and disintegrin domains; Northern blot showing high brain expression

   PMID:9693107

   Open questions at the time

   • Binding partners unknown
   • No functional assay demonstrating adhesion activity
   • Protein-level expression and localization not determined
3. 2002 Medium

   Detailed expression mapping revealed ADAM11 mRNA in neurons across the CNS, PNS, and select non-neural tissues during development, narrowing its likely function to neuron–neuron or neuron–glia interactions.

   Evidence In situ hybridization and Northern blot across adult and developing mouse tissues

   PMID:12088751

   Open questions at the time

   • Protein localization at subcellular level not addressed
   • No loss-of-function data yet available
   • Cell-type-specific roles unresolved
4. 2006 High

   Generation of ADAM11 knockout mice demonstrated that the protein is required for normal spatial learning, motor coordination, and inflammatory nociception, establishing its in vivo physiological importance without overt structural brain abnormalities.

   Evidence Gene-targeted knockout mice tested with Morris water maze, rotating rod, formalin paw, and acetic acid writhing assays

   PMID:16504143 PMID:16729981

   Open questions at the time

   • Molecular mechanism underlying behavioral deficits unknown
   • Synaptic partners unidentified
   • Pain-signaling pathway not delineated
5. 2008 High

   Identification of LGI1 and LGI4 as ligands for ADAM11 established a receptor–ligand system analogous to LGI–ADAM22 interactions, suggesting cell-type-specific signaling through the LGI–ADAM axis.

   Evidence Immunoprecipitation from mouse brain lysates, mass spectrometry, and quantitative cell-ELISA binding assays

   PMID:18974846

   Open questions at the time

   • Downstream signaling events triggered by LGI binding to ADAM11 not characterized
   • Structural basis of selectivity among ADAM11/22/23 for LGI ligands unknown
   • In vivo relevance of LGI4–ADAM11 interaction not tested
6. 2015 High

   ADAM11 was shown to be the critical anchor for Kv1.1/Kv1.2 channel complexes at the basket cell pinceau, and its loss abolished ephaptic inhibition of Purkinje cells while leaving chemical GABAergic transmission intact — defining ADAM11's primary electrophysiological function.

   Evidence Adam11 mutant mice analyzed by immunofluorescence, immunoelectron microscopy for Kv1 localization, and electrophysiology distinguishing ephaptic vs. chemical transmission

   PMID:26269648

   Open questions at the time

   • Direct physical interaction between ADAM11 and Kv1 subunits not biochemically demonstrated
   • Whether ADAM11 anchors Kv1 channels at other brain sites is unknown
   • Relationship between Kv1 anchoring and the spatial learning/nociception phenotypes is unresolved

• Key open questions include whether ADAM11 directly binds Kv1 channels or requires intermediary scaffolding partners, how LGI ligand binding modulates ADAM11's channel-anchoring function, and whether ADAM11 serves analogous scaffolding roles outside the cerebellum.
• No biochemical reconstitution of ADAM11–Kv1 complex
• Structural basis of ADAM11 function unresolved
• Role outside cerebellum and in peripheral nociceptive circuits not mechanistically defined