Kinesin-1 captures RNA cargo in its adaptable coils

Area of Science:

• Cell biology
• Molecular motors
• Structural biology

Background:

• Kinesin-1 is a vital microtubule motor protein essential for intracellular transport.
• Cargo adaptors mediate the selective delivery of diverse cellular components by kinesin-1.
• Interactions occur via kinesin light or heavy chains (KLCs or KHCs).

Purpose of the Study:

• To structurally characterize the interface between a KHC-cargo adaptor.
• To elucidate the mechanism by which adaptors facilitate motor-cargo binding.

Main Methods:

• X-ray crystallography to determine the structure of the KHC-aTm1 complex.
• Biochemical assays to confirm binding interactions.

Main Results:

• The study presents the first structural data of a KHC-cargo adaptor interface.
• An antiparallel heterotrimeric coiled-coil complex formed between the KHC carboxy tail and atypical tropomyosin (aTm1).
• This interaction enhances the direct binding of KHC to RNA, specifically oskar mRNA.

Conclusions:

• The KHC tail exhibits structural plasticity, serving as a versatile platform for protein-protein interactions.
• Cargo adaptors can modulate motor-RNA interfaces, thereby regulating transport processes.
• This work provides insights into the molecular mechanisms of directed intracellular transport.