HAUS7

HAUS7 is a subunit of the augmin complex that promotes γ-tubulin-dependent microtubule nucleation across multiple cellular contexts (PMID:23182369, PMID:31813605). In maturing mouse oocytes it localizes to the meiotic spindle, where its loss disrupts γ-tubulin recruitment to spindle poles, causing spindle disorganization and chromosome misalignment (PMID:23182369). In hippocampal neurons, HAUS7-containing augmin drives activity-dependent de novo nucleation of correctly oriented dynamic microtubules at presynaptic boutons, thereby controlling bidirectional synaptic vesicle transport and evoked exocytosis (PMID:31813605). HAUS7 is also a direct binding partner of DOCK3 and is transported under DOCK3 control to the neuronal growth cone, where TrkB-mediated phosphorylation of DOCK3 at Y562 releases HAUS7 to permit microtubule assembly; loss of Haus7 in mice reduces microtubule formation and axon regeneration after optic nerve crush (PMID:40712007). Separately, HAUS7 binds the deubiquitinase UCH37 (UCHL5) via the UCH37 C-terminal extension and competitively blocks the UCH37–S14/PA700 proteasome interaction in vitro (PMID:11163772).

1. 2001 Medium

   Established the first molecular partner of HAUS7, linking it to deubiquitinase regulation by showing it can competitively interrupt UCH37 association with the proteasome.

   Evidence Yeast two-hybrid, in vitro binding, and co-immunoprecipitation mapping the UCH37 C-terminal extension as the interaction surface

   PMID:11163772

   Open questions at the time

   • No cellular consequence of the HAUS7–UCH37 interaction demonstrated in vivo
   • Relationship between this proteasome-associated role and HAUS7's microtubule functions unresolved
   • Competitive blocking shown only in vitro
2. 2013 Medium

   Demonstrated a direct cytoskeletal role by showing HAUS7 is required for γ-tubulin-dependent spindle organization during meiotic maturation.

   Evidence siRNA knockdown in mouse oocytes with immunofluorescence and spindle/chromosome phenotype analysis

   PMID:23182369

   Open questions at the time

   • Mechanism by which HAUS7 promotes γ-tubulin recruitment not resolved at molecular level
   • Single-lab loss-of-function without rescue
   • Augmin complex composition in oocytes not characterized
3. 2019 Medium

   Extended HAUS7-dependent microtubule nucleation to neurons, connecting augmin activity to presynaptic microtubule generation and synaptic vesicle traffic.

   Evidence siRNA knockdown in hippocampal neurons/slices with live EB3-EGFP plus-end imaging and synaptic vesicle transport/exocytosis assays

   PMID:31813605

   Open questions at the time

   • How activity signals trigger augmin-dependent nucleation at boutons unknown
   • Other augmin subunit contributions not dissected
   • Single-lab study
4. 2025 High

   Defined a regulated, signaling-controlled mechanism for HAUS7 in axon regeneration, showing TrkB-driven DOCK3 phosphorylation gates HAUS7 release to permit microtubule assembly.

   Evidence DOCK3–HAUS7 binding assay, Y562 phosphosite mutagenesis, Haus7 knockout mice, optic nerve crush, MT formation and transcriptome analysis

   PMID:40712007

   Open questions at the time

   • Structural basis of phosphorylation-dependent HAUS7 dissociation not determined
   • Whether augmin complex assembly is required at the growth cone unaddressed
   • Link to the meiotic/synaptic nucleation roles not integrated

• How HAUS7's proteasome-regulatory interaction with UCH37 relates mechanistically to its augmin-dependent microtubule nucleation functions remains unresolved.
• No study reconciles the UCH37/proteasome role with the microtubule role
• No structural model of HAUS7 within augmin reported in the corpus