A direct interaction between CENTLEIN and RABIN8 is required for primary cilium formation

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Primary cilia are vital for mammalian development and tissue health.
• Cilia defects cause human disorders known as ciliopathies.
• RABIN8 localization at the pericentrosome is an early step in ciliogenesis.

Purpose of the Study:

• To investigate the role of CENTLEIN in ciliogenesis.
• To elucidate the interaction between CENTLEIN and RABIN8.
• To understand the functional significance of this interaction in primary cilia formation.

Main Methods:

• Depletion of CENTLEIN in human retinal pigment epithelial cells and murine fibroblasts.
• Analysis of RABIN8 localization using immunofluorescence.
• Co-immunoprecipitation assays to confirm protein interactions.
• Rescue experiments with full-length and mutant CENTLEIN constructs.
• Functional assays with activated RAB8A.

Main Results:

• CENTLEIN depletion led to persistent RABIN8 accumulation on the pericentrosome and loss of primary cilia.
• CENTLEIN directly interacts with RABIN8 via a specific 31-amino acid region in the RABIN8 GEF domain.
• Full-length CENTLEIN, but not a mutant lacking the RABIN8-binding site, rescued ciliogenesis defects.
• Activated RAB8A partially restored cilia in CENTLEIN-depleted cells.

Conclusions:

• CENTLEIN is essential for proper RABIN8 localization and primary cilia formation.
• The CENTLEIN-RABIN8 interaction is critical for ciliogenesis.
• This interaction represents a potential therapeutic target for ciliopathies.