KATNIP

Cilia effects upon perturbation of KATNIP

Cilia number / % ciliated:

Decreased cilia number

Loss-of-function effect:

Shorter cilia

Phenotypes

Mouse phenotype:

no spontaneous movement, enlarged epididymis, decreased locomotor activity, abnormal epididymis morphology

Human ciliopathy phenotype:

Joubert syndrome

Ciliopathy associations

• Joubert Syndrome

References: PMID:26714646, PMID:36580738

Subcellular localization

basal body, cilia

References: PMID:41410385, PMID:41005307, PMID:27245168, PMID:26714646, PMID:37665596

Functional category

• Ciliary assembly/disassembly
• Actin & cytoskeleton regulation
• Cilia length regulation

Function

Binds to and stabilise microtubule networks when overexpressed, it interacts with intraflagellar transport components and katanins associated with severing. Form a complex that regulates microtubule dynamics as well as ciliary functions. Negative regulator of ciliary length. Mutated in Joubert syndrome (27245168, 26714646). KATNIP binding with CILK1 … resulted in a profound increase in phosphorylation of known CILK1 substrates and suppression of cilia length. (37665596) In a serum-starvation ciliogenesis assay, human fibroblast cells derived from patients with mutation display a reduced number of ciliated cells with abnormally long cilia. (GeneCards) KATNIP disease variants fail to support CILK1 activation, leading to loss of cilia length restriction and altered ciliation rate. KATNIP uses separate domains to bind and activate CILK1.