A primary microcephaly protein complex forms a ring around parental centrioles

Area of Science:

• Cell Biology
• Neuroscience
• Genetics

Background:

• Autosomal recessive primary microcephaly (MCPH) is a neurodevelopmental disorder characterized by reduced brain size.
• MCPH arises from mutations in genes encoding centrosomal proteins, but the precise centrosome dysfunction remains unclear.
• Centrosomes are critical for cell division and organization, and their proper function is vital for brain development.

Purpose of the Study:

• To investigate the role of the CEP63 gene in autosomal recessive primary microcephaly (MCPH).
• To elucidate the function of CEP63 and its interaction with other centrosomal proteins in maintaining centrosome number and integrity.
• To understand how CEP63 dysfunction impacts human brain development, particularly cerebral cortex growth.

Main Methods:

• Genetic analysis to identify mutations in CEP63 in MCPH patients.
• Biochemical assays to study the interaction between CEP63 and CEP152.
• Super-resolution microscopy to visualize the localization and structure of CEP63 and CEP152 at the centrosome.

Main Results:

• A homozygous MCPH-causing mutation was identified in the human CEP63 gene.
• CEP63 forms a complex with CEP152, and together they are essential for maintaining normal centrosome numbers.
• CEP63 and CEP152 form a ring structure at the proximal end of the parental centriole, which is disrupted in CEP63-deficient cells.

Conclusions:

• The CEP152-CEP63 ring structure is crucial for normal neurodevelopment.
• Impairment of this ring structure, particularly due to CEP63 mutations, significantly affects human cerebral cortex growth.
• This study provides insights into the molecular mechanisms underlying MCPH and highlights the importance of centrosome integrity in brain development.