UNC

PF3D7_1420200 (UNC) is a UCS-family myosin-specific chaperone in Plasmodium falciparum required for the production of folded, functional PfMyoA (class XIV myosin A) (PMID:28978649). Co-expression of UNC was necessary to obtain milligram quantities of active full-length PfMyoA in a baculovirus/Sf9 recombinant system, establishing that UNC acts in the folding/production of this myosin motor (PMID:28978649). Beyond this chaperone requirement demonstrated in a single reconstitution study, no further mechanistic detail — including the structural basis of substrate recognition, cellular localization, or in vivo function of UNC — has been characterized in the available corpus.

1. 2017 Medium

   It was unknown whether PfMyoA required a dedicated chaperone to fold into an active motor; co-expression experiments showed the UCS-family chaperone UNC is necessary to produce functional PfMyoA, establishing UNC as the myosin-specific folding factor for the class XIV motor.

   Evidence Recombinant expression of full-length PfMyoA in a baculovirus/Sf9 system requiring co-expression of the UCS chaperone

   PMID:28978649

   Open questions at the time

   • Single study, single lab, single method — chaperone requirement not independently reconstituted
   • Structural basis of UNC binding to and folding of PfMyoA not defined
   • In vivo requirement and localization of UNC in the parasite not tested

• How UNC recognizes and folds PfMyoA at the molecular level, and whether it is required for glideosome function and parasite motility in vivo, remains unresolved.
• No structural model of the UNC–PfMyoA interaction
• No genetic loss-of-function or localization data in the parasite
• No evidence on whether UNC chaperones other myosins