MTMR9 is a catalytically inactive pseudophosphatase that lacks the catalytic cysteine in the CX5R motif

MTMR9 forms heterodimeric complexes with MTMR6, MTMR7, and MTMR8, modulating their localization and substrate specificity

MTMR9 recruits MTMR6 and MTMR8 to the intermediate compartment and Golgi apparatus, sustaining Golgi integrity and ER-to-Golgi transport

No direct experimental data exist for A0A8B6GS20 in Mytilus galloprovincialis; all functional annotations are inferred from orthologous proteins in model organisms

Only residues 362-588 align to human MTMR9 (residues 313-542). Residues 1-361 are D8C_UMOD-type repeats; the model is a partial/fused MTMR9 gene model.

The retained phosphatase-like region carries the MTMR9-type inactive motif VHGSEGFDTT, with Gly and Thr at the positions of the MTMR6 catalytic Cys and Arg.

The full-length M. galloprovincialis MTMR9-type models from ORF MGAL_10B079678 are 97.2% identical over the shared C-terminal 246 residues.

MTMR9 dimerises with MTMR6, MTMR7 and MTMR8, increases their 3-phosphatase activity and sets substrate preference; the MTMR8/R9 complex inhibits autophagy.

MTMR9 heteromerises with MTMR6, increases its 3-phosphatase activity and stabilises both proteins.

Myotubularins are lipid phosphatases; inactive members pair with active ones (MTMR8 with MTMR9).

C. elegans MTM-6 and MTM-9 act as a complex in coelomocyte endocytosis and their loss disorganises PI3P localisation.

The MTM-6/MTM-9 complex dephosphorylates PI3P and regulates MIG-14/Wls recycling in Wnt-producing cells.