CENPA

CENPA Full Name

centromere protein A

CENPA Introduction

The Centromere Protein A, commonly known as CENPA, is a critical structural protein encoded by the CENPA gene in humans. It serves as the fundamental epigenetic mark that defines the centromere—the specialized region of a chromosome where sister chromatids are held together and where the kinetochore forms during cell division. Without CENPA, the machinery of mitosis would essentially lose its "anchor," leading to catastrophic errors in how genetic material is distributed to daughter cells.CENPA is a specialized histone H3 variant. While standard H3 proteins help wrap DNA into nucleosomes across the entire genome, CENPA is strictly localized to centromeric chromatin. Evolutionarily, it has adapted rapidly to maintain its function despite the highly repetitive and fast-evolving nature of centromeric DNA sequences. This "centromere paradox" highlights CENPA's role as the primary determinant of centromere identity, which is maintained through an epigenetic mechanism rather than a specific DNA sequence alone.

Figure 1. Strcuture of CENPA.

Core Function and Molecular Mechanism
CENPA (Centromere Protein A) is a fundamental histone H3 variant that plays an indispensable role in chromosome biology by defining centromere identity. Unlike conventional histones that are deposited throughout the genome, CENPA specifically replaces canonical H3 in the nucleosomes of centromeric chromatin, creating a unique epigenetic mark that persists through cell divisions. This specialized nucleosome structure serves as the foundation for kinetochore assembly, the protein complex responsible for microtubule attachment and chromosome segregation during mitosis. The protein contains a conserved histone fold domain and a critical CATD (CENPA targeting domain) that directs its exclusive localization to centromeres and enables its more rigid nucleosomal conformation compared to conventional H3-containing nucleosomes.

Clinical Significance in Oncology and Autoimmunity
Due to its central role in cell division, dysregulation of CENPA is frequently linked to human diseases. In many forms of cancer, CENPA is significantly overexpressed, which can lead to its mistargeting to non-centromeric regions of the genome. This displacement contributes to genomic instability and aneuploidy, hallmarks of aggressive tumor progression. Furthermore, CENPA is a well-known autoantigen in systemic sclerosis (Scleroderma); patients often develop anti-centromere antibodies (ACAs) that specifically target this protein, making it a vital biomarker in clinical diagnostics.

Alternate Names for CENPA

CENPA; centromere protein A; Cenp-A; histone H3-like centromeric protein A; centrosomin A; centromere autoantigen A;

• Autoimmunity Catalogue