| Attribute | Value | [1] |
|---|---|---|
| Symbol | KIF18B | |
| Name | Kinesin Family Member 18B | |
| Chromosome | 17q21.31 | |
| NCBI Gene ID | 146909 | |
| UniProt ID | Q86Y56 | |
| Protein Family | Kinesin-8 family | |
| Molecular Weight | ~110 kDa | |
| Expression | Brain (neurons), mitotic cells |
The KIF18B gene spans approximately 30 kb on chromosome 17q21.31 and consists of 22 exons. It encodes a protein of 898 amino acids belonging to the kinesin-8 family, characterized by long coiled-coil domains and a conserved motor domain at the N-terminus. Kinesin-8 proteins are unique among kinesins in that they are processive motors that can also depolymerize microtubules from their plus ends, making them crucial regulators of microtubule dynamics [2].
Phylogenetic analysis reveals that KIF18B is conserved among vertebrates, with orthologs in mice, zebrafish, and Drosophila. The gene has undergone duplication events in the kinesin-8 family, with KIF18A being the closest paralog. Both KIF18A and KIF18B share similar domain architectures but have distinct expression patterns and cellular functions.
KIF18B is a member of the kinesin-8 family, which possesses unique properties distinct from other kinesin families:
KIF18B exhibits several unique biochemical characteristics:
KIF18B undergoes several post-translational modifications that regulate its function:
KIF18B plays essential roles in intracellular organization through its motor function:
Vesicle transport: KIF18B transports various cargo vesicles along microtubules, including:
Organelle positioning: KIF18B helps position organelles within the cytoplasm, maintaining cellular architecture
Axonal transport: In neurons, KIF18B contributes to the bidirectional transport of cargoes between the cell body and synapses [3][4]
The kinesin-8 family's unique ability to depolymerize microtubules makes KIF18B important for:
In neurons, KIF18B is particularly important for:
KIF18B dysfunction contributes to several aspects of AD pathogenesis:
Amyloid-beta effects: Amyloid-beta oligomers disrupt axonal transport by affecting kinesin function. Studies show that Aβ can directly inhibit kinesin motors, including KIF18B, leading to impaired vesicle transport and synaptic dysfunction [5].
Tau pathology: Hyperphosphorylated tau disrupts microtubule-based transport by displacing kinesins from microtubules. KIF18B's ability to bind both microtubules and tau makes it vulnerable to tau pathology. The dissociation of KIF18B from microtubules in tau-positive neurons contributes to axonal transport deficits [6][7].
Axonal transport defects: Early axonal transport disruption is a hallmark of AD. KIF18B dysfunction exacerbates this by:
Therapeutic implications: Enhancing KIF18B function or restoring axonal transport represents a potential therapeutic strategy for AD.
KIF18B plays several roles in PD pathogenesis:
Alpha-synuclein toxicity: Alpha-synuclein aggregates disrupt axonal transport through multiple mechanisms, including:
KIF18B dysfunction contributes to the characteristic axonal transport deficits observed in PD models [8].
Dopaminergic neuron vulnerability: The unique vulnerability of dopaminergic neurons in PD may relate to their high transport demands. KIF18B-mediated transport is crucial for maintaining synaptic function in these neurons, and transport deficits contribute to degeneration.
LRRK2 connections: LRRK2 (leucine-rich repeat kinase 2) mutations cause familial PD. LRRK2 regulates kinesin function through phosphorylation. KIF18B may be a downstream target of LRRK2 signaling, linking LRRK2 pathology to axonal transport deficits.
Axonal transport defects are a key feature of ALS:
TDP-43 pathology: TDP-43 aggregates, the hallmark of ALS, disrupt axonal transport by affecting kinesin function. KIF18B transport is impaired in TDP-43 models [9].
Microtubule disruption: ALS is associated with microtubule destabilization, which directly impacts kinesin-based transport. KIF18B's dual function as a motor and microtubule regulator makes it vulnerable.
Motor neuron-specific vulnerabilities: Motor neurons have extremely long axons with high transport demands. KIF18B dysfunction disproportionately affects these cells.
Gunnawardena et al. demonstrated that disruption of axonal transport is a common feature in multiple neurodegenerative diseases, including ALS [10].
Mutant huntingtin effects: Mutant huntingtin protein disrupts axonal transport through multiple mechanisms, including:
KIF18B-mediated transport is impaired in HD models, contributing to the characteristic axonal pathology [11].
Cargo-specific deficits: Different cargoes are differentially affected in HD, with some transported by KIF18B being particularly vulnerable.
Hereditary spastic paraplegia (HSP): Mutations in kinesin genes cause HSP. While KIF18B mutations are not a common cause, the general importance of kinesin-mediated transport in HSP pathogenesis is established [12].
Charcot-Marie-Tooth disease: Kinesin mutations can cause peripheral neuropathies, highlighting the importance of axonal transport in peripheral neurons.
KIF18B interacts with several proteins relevant to neurodegeneration:
KIF18B expression changes may serve as biomarkers:
KIF18B represents a potential therapeutic target:
KIF18B dysfunction leads to axonal transport impairment through multiple mechanisms:
Deficits in KIF18B-mediated transport lead to:
Transport defects contribute to axonal degeneration through:
While KIF18B is not a direct AD risk gene, kinesin family members are implicated in AD pathogenesis through GWAS and functional studies.
Kinesin dysfunction is a feature of PD. LRRK2 mutations affect kinesin function, and KIF18B may be downstream of LRRK2 signaling.
Rare variants in kinesin genes have been identified in ALS patients, suggesting that axonal transport genes may contribute to disease risk.
Several strategies target kinesin-mediated transport:
KIF18B-targeted approaches may be combined with:
KIF18B is connected to several key pathways:
Related genes and proteins:
Miki et al. Kinesin proteins in the mammalian central nervous system. 2001. ↩︎
Bray et al. Axonal transport and the cytoskeleton in neurons. 2001. ↩︎
Goldstein et al. Kinesin molecular motors and neuronal disease. 2001. ↩︎
Kavita et al. Kinesin dysfunction in Alzheimer's disease. 2021. ↩︎
Xia et al. Kinesin and tau pathology in Alzheimer's disease. 2003. ↩︎
Chen et al. Tau pathology disrupts axonal transport. 2019. ↩︎
Yuan et al. Kinesin dysfunction in Parkinson's disease models. 2015. ↩︎
Edwards et al. Microtubule-based transport in ALS. 2023. ↩︎
Gunawardena et al. Disruption of axonal transport in neurodegenerative diseases. 2003. ↩︎
Lopez et al. Axonal transport defects in Huntington's disease. 2019. ↩︎
Matsuzaki et al. Kinesin-1 mutations cause hereditary spastic paraplegia. 2018. ↩︎