AP3M1

AP3M1 is a subunit of the AP-3 adaptor protein complex whose abundance is governed by the complex's assembly dynamics (PMID:29032074). Within this complex, AP3B1 acts as a rate-limiting assembly factor: depletion of AP3B1 reduces AP3M1 protein abundance, indicating that AP3M1 stability and stoichiometry depend on co-regulation with AP3B1 (PMID:29032074). Beyond this co-regulatory relationship within the AP-3 complex, no further mechanistic detail for AP3M1 has been characterized in the available corpus.

1. 2017 Medium

   It was unclear how AP3M1 abundance is controlled within the AP-3 complex; proteomic analysis with experimental confirmation showed AP3B1 is a rate-limiting assembly factor whose loss reduces AP3M1 levels, establishing that AP3M1 stoichiometry is co-regulated by AP3B1.

   Evidence Proteomics across CPTAC/TCGA datasets combined with experimental confirmation of the AP3B1–AP3M1 interaction and co-regulation

   PMID:29032074

   Open questions at the time

   • Specific orthogonal methods confirming the interaction are not detailed
   • Cargo selectivity and vesicle-trafficking function of AP3M1 not addressed
   • Subcellular localization of AP3M1 not established in this finding

• The direct molecular activity, cargo-recognition role, and subcellular localization of AP3M1 within AP-3-mediated trafficking remain uncharacterized in the available corpus.
• No defined molecular function for AP3M1
• No characterized localization
• No identified cargo or trafficking pathway