NuSAP Protein: Key to Centriole Integrity & Preventing Microcephaly & MVA Syndrome

Biologists at the National University of Singapore (NUS) have identified a crucial role for the protein NuSAP in maintaining the stability of centrioles, tiny structures essential for accurate cell division. This discovery, published in the journal Advanced Science, sheds light on the mechanisms underlying developmental disorders like microcephaly and mosaic variegated aneuploidy (MVA) syndrome. Understanding how NuSAP functions as a “guardian” of centriole integrity could open new avenues for research into these and other conditions linked to chromosome instability.

Centrosomes and the Challenge of Cell Division

Successful cell division hinges on the precise duplication and distribution of genetic material. This process is orchestrated by centrosomes, often described as the cell’s “control centers.” Centrosomes organize microtubules, which form the mitotic spindle – the structure responsible for separating chromosomes. At the heart of each centrosome are two centrioles, cylindrical organelles that must remain tightly linked after duplication and separate only at a specific point in the cell cycle. Disruptions to this coordination can lead to abnormal centrosome numbers, chromosome mis-segregation, and genomic instability, all of which are implicated in developmental defects and cancer.

Until recently, the molecular mechanisms safeguarding centriole structure throughout the cell cycle remained largely unknown. The NUS team, led by Associate Professor LIOU Yih-Cherng, has now begun to fill in those gaps, focusing on the function of NuSAP.

NuSAP: Beyond Spindle Stabilization

NuSAP, or Nucleolar and Spindle Associated Protein, was previously known for its role in stabilizing microtubules during mitosis. However, this new research reveals that NuSAP’s protective function extends earlier in the cell cycle, directly impacting centriole structure. Using super-resolution imaging and biochemical assays, the researchers demonstrated that a loss of NuSAP leads to damage within the centriole’s internal scaffold and premature separation of the centriole pair. Bioengineer.org highlights the significance of this finding, describing NuSAP as a “centriol guardian.”

The team discovered that NuSAP is critical for recruiting a complex of proteins – the CEP57–CEP63–CEP152 torus complex – that wraps around the centriole, maintaining the connection between the two structures. NuSAP physically binds to CEP57, one of the proteins in this complex, and helps position it correctly just before cell division begins. This precise positioning is essential for ensuring the centrioles remain engaged until the appropriate time.

Implications for Developmental Disorders

The findings have significant implications for understanding developmental disorders like microcephaly, a condition characterized by an abnormally small head, and MVA syndrome, a rare chromosomal disorder. Both conditions are associated with chromosome instability, and the NUS research suggests that defects in NuSAP function could contribute to these instabilities. Dr. Shiyu Zhang, a Research Fellow at the NUS Department of Biological Sciences, explained, “Accurate cell division is fundamental to human development. Our study shows that the protein NuSAP acts as a guardian of centrosome integrity. When this protection fails, chromosome errors can accumulate, a hallmark of disorders such as microcephaly and MVA syndrome.”

Methodology and Evidence

The research team employed a combination of advanced techniques to unravel NuSAP’s role. Super-resolution microscopy allowed them to visualize the intricate details of centriole structure and protein interactions. Biochemical assays were used to confirm the physical binding between NuSAP and CEP57, and to assess the impact of NuSAP loss on centriole stability. The study, published January 30th, 2026, details the experimental procedures and data analysis, providing a robust foundation for the conclusions drawn. The full study is available in Advanced Science (DOI: 10.1002/advs.202515192).

It’s important to note that this research focuses on the fundamental mechanisms of centriole stability. Further studies are needed to determine the specific genetic mutations or environmental factors that might disrupt NuSAP function in humans and contribute to developmental disorders. The study also doesn’t address potential therapeutic interventions targeting NuSAP, though the identification of its critical role opens the door for such investigations.

What’s Next: Validation and Therapeutic Potential

The NUS team’s findings are likely to spur further research in the field. The next steps will involve validating these results in different cell types and model organisms. Researchers will also seek to identify the specific molecular signals that regulate NuSAP activity and its interaction with the CEP57–CEP63–CEP152 complex.

Looking ahead, understanding how to restore or enhance NuSAP function could potentially lead to new therapeutic strategies for treating developmental disorders associated with chromosome instability. However, any such interventions would require extensive preclinical and clinical testing to ensure safety and efficacy. The team’s work provides a crucial foundation for these future endeavors, offering a new target for understanding and potentially addressing these complex genetic conditions.