AKIT7

AKIT7 (PF3D7_0410900) is an apicomplexan-specific kinetochore protein identified through interactomics and deep homology searches, localizing to kinetochores as part of a multiprotein kinetochore assembly organized into at least four biochemically and spatially distinct compartments (PMID:36006241). During activated male gametogenesis in P. berghei, AKIT7 physically associates with the atypical Plasmodium Arp2/3 complex, being recovered in ARPC1-GFP co-immunoprecipitations specifically from activated but not non-activated gametocytes (PMID:40514561). This activation-dependent association places AKIT7 at the kinetochore-spindle interface: loss of ARPC1 causes kinetochores to partially detach from spindles and reside freely in the nucleus, implicating the AKIT7-associated Arp2/3 complex in kinetochore-spindle attachment during chromosome segregation, although AKIT7 itself has not been directly manipulated (PMID:40828051). No direct loss-of-function experiment targeting AKIT7 has been reported in the available corpus; its role is inferred from complex membership and the phenotypes of interacting subunits.

1. 2022 Medium

   Establishing that AKIT7 is a bona fide kinetochore component answered whether this uncharacterized apicomplexan protein has a defined subcellular assignment, placing it within the parasite's divergent kinetochore machinery.

   Evidence Interactomics (IP-MS) plus deep homology searches with microscopy-based localization

   PMID:36006241

   Open questions at the time

   • No direct functional manipulation of AKIT7 to test its requirement for kinetochore assembly
   • Which of the four kinetochore compartments AKIT7 occupies and its direct binding partners within them are not resolved
2. 2023 Low

   Co-variation of AKIT7 with ARK2 and EB1 in pulldown data addressed which spindle-associated structures AKIT7 belongs to, linking it to the ARK2/EB1 kinetochore-spindle module during gametocyte development.

   Evidence EB1-GFP and ARK2-GFP co-IP mass spectrometry with PCA of spectral counts in gametocytes

   PMID:37704606

   Open questions at the time

   • Co-variation in PCA is an indirect association, not a demonstrated physical interaction
   • No direct manipulation of AKIT7 to test functional relevance of the ARK2/EB1 association
3. 2025 Low

   Identifying AKIT7 as an ARPC1 interactor and observing kinetochore detachment upon ARPC1 loss addressed how kinetochores couple to spindles, implicating the AKIT7-associated Arp2/3 complex in this attachment specifically during activated male gametogenesis.

   Evidence ARPC1-GFP co-IP/MS with activation-dependent controls (P. berghei); ARPC1 genetic disruption with kinetochore imaging and AlphaFold prediction

   PMID:40514561 PMID:40828051

   Open questions at the time

   • Kinetochore-attachment function is inferred from the ARPC1 knockout phenotype, not from disrupting AKIT7 itself
   • Whether the AKIT7-ARPC1 association is direct or bridged by other subunits is unknown
   • The molecular basis of AKIT7's activation-dependent recruitment is not defined
4. 2026 Low

   Detection of AKIT7 in the ARK1 interactome under cross-linking and its stage-biased association with SKA/PP1 modules addressed when AKIT7 engages checkpoint/kinase machinery, pointing to preferential engagement during meiosis versus male mitosis.

   Evidence Native and cross-linked ARK1-3xHA IP-MS compared across meiotic and mitotic stages (P. berghei)

   PMID:42323312

   Open questions at the time

   • Interaction detected only under high cross-linking, indicating a labile or indirect association
   • The MAD1/spindle-assembly-checkpoint homology annotation is not backed by functional checkpoint assays on AKIT7
   • No direct functional manipulation of AKIT7 in meiosis versus mitosis

• Whether AKIT7 is itself required for kinetochore assembly, kinetochore-spindle attachment, or spindle checkpoint function remains unresolved, as all functional inferences to date rest on partner phenotypes rather than direct AKIT7 loss-of-function.
• No conditional knockout or knockdown of AKIT7 itself
• No structural or biochemical demonstration of a direct AKIT7 binding partner
• MAD1/checkpoint activity attributed to AKIT7 by homology remains functionally untested