PIP2

PIP2 (PF3D7_1431100) is a component of a PhIL1-associated protein complex that resides in the inner membrane complex (IMC) of Plasmodium falciparum merozoites and co-exists there with the glideosome motor complex (PMID:34324609). It physically interacts with PhIL1, and within this complex is found alongside PfGAPM2 and PfALV5 (PMID:34324609). Functionally, conditional downregulation of PIP2 disrupts merozoite segmentation and abolishes the post-attachment reorientation/gliding step, blocking erythrocyte invasion while leaving initial RBC attachment intact (PMID:34324609). Beyond its membership in this PhIL1 complex and its role in merozoite segmentation and invasion, no further mechanistic detail — such as a defined biochemical activity or the structural basis of its interactions — has been characterized in the available corpus.

1. 2021 Low

   To place PF3D7_1431100 spatially, a proximity-labeling screen tested whether it associates with the IMC scaffold protein PhIL1, establishing its subcellular compartment.

   Evidence BioID proximity-dependent biotin identification with PhIL1 as bait, followed by mass spectrometry, in asexual blood-stage P. falciparum

   PMID:33830607

   Open questions at the time

   • Proximity labeling does not distinguish direct interaction from mere neighborhood within the IMC
   • No functional role for PF3D7_1431100 was tested in this screen
2. 2021 Medium

   To define whether PF3D7_1431100 is a bona fide member of a PhIL1 complex, its physical interaction with PhIL1 was tested, establishing it as a component of a distinct IMC complex containing PfGAPM2 and PfALV5.

   Evidence Co-immunoprecipitation/pulldown and mass spectrometry within the merozoite IMC of P. falciparum

   PMID:34324609

   Open questions at the time

   • Whether the PhIL1 interaction is direct or bridged by other complex members is not resolved
   • Stoichiometry and structural architecture of the complex are unknown
3. 2021 Medium

   To determine the cellular function of PF3D7_1431100, its depletion was linked to specific stages of the invasion program, establishing it as required for merozoite segmentation and post-attachment reorientation/gliding but dispensable for initial attachment.

   Evidence Conditional knockdown/gene disruption with invasion, reorientation/gliding assays, and immunofluorescence in P. falciparum

   PMID:34324609

   Open questions at the time

   • The molecular activity by which PF3D7_1431100 supports segmentation and gliding is undefined
   • Whether the segmentation and invasion defects are separable or a single upstream cause is not established
   • No structural or enzymatic characterization of the protein

• The biochemical mechanism by which PF3D7_1431100 couples the PhIL1 complex to glideosome-driven reorientation and invasion remains unknown.
• No defined molecular/enzymatic activity for PF3D7_1431100
• No structural model of PF3D7_1431100 or its interface with PhIL1
• Functional role tested only in P. falciparum blood-stage merozoites