PRR14L

PRR14L is a scaffold protein that supports mitotic fidelity and constrains the spindle assembly checkpoint (SAC) (PMID:41279925, PMID:42160513). Proximity labeling places PRR14L in physical proximity to the PP2A-B56 phosphatase complex and the spindle assembly factor TACC3, defining it as a scaffold linking a PP2A-TACC3 axis during cell division (PMID:41279925, PMID:42160513). Consistent with this role, loss of PRR14L prolongs SAC-dependent mitotic arrest upon microtubule depolymerization, indicating that PRR14L normally limits the duration of checkpoint-mediated arrest (PMID:41279925, PMID:42160513); when the checkpoint is abrogated by MPS1 inhibition, PRR14L-deficient cells instead undergo catastrophic mitotic errors, showing that PRR14L is required to maintain mitotic fidelity when checkpoint signaling is compromised (PMID:41279925, PMID:42160513). In the hematopoietic lineage, PRR14L loss-of-function skews CD34+ differentiation toward monocytes at the expense of neutrophils, a CMML-like phenotype (PMID:30573780). Beyond these mitotic and differentiation observations, the molecular logic by which PRR14L coordinates PP2A-B56 and TACC3 has not been resolved in the available corpus.

1. 2018 Medium

   Established that PRR14L loss-of-function has a defined cellular consequence, linking the gene to hematopoietic differentiation control and hinting at a cell-division role.

   Evidence shRNA knockdown in human CD34+ cells with in vitro differentiation assays and cellular localization studies

   PMID:30573780

   Open questions at the time

   • No molecular mechanism connecting PRR14L to the differentiation skew
   • Localization role in cell division only suggested, not defined
   • Single lab, single method set
2. 2025 Medium

   Identified the physical interaction network of PRR14L, placing it as a scaffold proximal to the PP2A-B56 phosphatase and TACC3.

   Evidence TurboID proximity labeling mass spectrometry

   PMID:41279925 PMID:42160513

   Open questions at the time

   • Proximity labeling does not establish direct binding or stable complex stoichiometry
   • Functional consequence of the PP2A-TACC3 link not dissected
   • Single lab
3. 2025 Medium

   Defined PRR14L as a negative regulator of SAC-dependent arrest duration and as a guardian of mitotic fidelity when the checkpoint is bypassed.

   Evidence CRISPR/Cas9 loss-of-function with live-cell mitotic arrest assays, MPS1 inhibitor treatment, and a genome-wide CRISPR screen

   PMID:41279925 PMID:42160513

   Open questions at the time

   • Mechanism by which PRR14L limits arrest duration unresolved
   • How PRR14L loss produces catastrophic errors under MPS1 inhibition not mechanistically mapped
   • Connection between the mitotic role and the hematopoietic phenotype untested

• How PRR14L mechanistically coordinates PP2A-B56 phosphatase activity and TACC3 to control checkpoint timing and segregation fidelity, and whether this explains its hematopoietic differentiation role, remains unresolved.
• No structural or biochemical model of the scaffold function
• Direct substrates/dephosphorylation targets of the PRR14L-PP2A axis unknown
• Causal link between mitotic defects and CMML-like differentiation skew not established