High-intensity light disrupts intracellular organelle dynamics via microtubule depolymerization

Area of Science:

• Cell Biology
• Organelle Transport
• Cytoskeleton Dynamics

Background:

• Chromatophores are specialized cells for pigment granule translocation.
• Previous research linked low-intensity light-induced aggregation to Opsin 3.
• High-intensity light effects on organelle transport remain less understood.

Purpose of the Study:

• To investigate the effects of prolonged high-intensity white light (HIWL) on xanthosomes in fish chromatophores.
• To elucidate the underlying molecular mechanisms of HIWL-induced xanthosome dispersion.
• To determine if this mechanism is conserved in other cell types.

Main Methods:

• Exposure of fish xanthophores to prolonged HIWL (10,000 lux).
• Ex vivo illumination and pharmacological treatments.
• Analysis of intracellular calcium levels and microtubule dynamics.
• Experiments on human cell lines (HeLa, HEK293T) under HIWL.

Main Results:

• HIWL induces reversible xanthosome dispersion, distinct from low-intensity aggregation.
• Dispersion is mediated by microtubule depolymerization due to elevated intracellular Ca2+ from IP3R channels.
• This mechanism is also observed in HeLa and HEK293T cells exposed to HIWL.

Conclusions:

• HIWL triggers organelle dispersion via a novel Ca2+- and microtubule-dependent pathway.
• This light-induced cellular response is conserved across different species and cell types.
• Findings expand understanding of high-intensity light's impact on intracellular transport and cytoskeleton.