The human phosphatase CDC14A modulates primary cilium length by regulating centrosomal actin nucleation

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• CDC14A is a proline-directed phosphatase implicated in autosomal-recessive deafness due to defective kinocilia.
• Previous studies suggest a role for CDC14A in cilia formation in various organisms, but its precise function in human cilia remains elusive.

Purpose of the Study:

• To elucidate the role of human CDC14A in primary cilia formation and length regulation.
• To identify novel substrates and pathways regulated by CDC14A during ciliogenesis.

Main Methods:

• Utilized human RPE1 cells with a phosphatase-dead CDC14A mutant and wild-type cells.
• Performed phospho-proteome analysis on ciliated RPE1 cells.
• Investigated the interaction of CDC14A with drebrin and Arp2.
• Assessed endocytosis and vesicle targeting during ciliogenesis.

Main Results:

• Phosphatase-dead CDC14A cells exhibited longer cilia, while CDC14A overexpression shortened them.
• Identified actin-associated and microtubule-binding proteins, including drebrin, as CDC14A substrates.
• Demonstrated that CDC14A counteracts CDK5-dependent drebrin phosphorylation and regulates Arp2 recruitment to centrosomes.
• Showed CDC14A also influences endocytosis and myosin Va vesicle targeting in a drebrin-independent manner.

Conclusions:

• Human CDC14A plays a multifaceted role in primary cilia formation.
• CDC14A regulates cilia length through drebrin-dependent and independent pathways involving actin organization, endocytosis, and vesicle transport.