Tunable Cellular Localization and Extensive Cytoskeleton-Interplay of Reflectins

Area of Science:

• Biophysics
• Molecular Biology
• Evolutionary Biology

Background:

• Reflectin proteins are natural copolymers forming Bragg lamellae for dynamic structural coloration in iridocytes.
• The precise biological functions and intracellular mechanisms of reflectins remain incompletely understood.
• Understanding reflectin localization and transport is key to elucidating their role in biophotonics.

Purpose of the Study:

• To investigate the intracellular localization preferences of different reflectin variants (A1, A2, B1, C).
• To explore the mechanism of reflectin entry into Bragg lamellae, potentially involving nuclear access.
• To determine the role of the cytoskeleton in the organization and transport of reflectin proteins.

Main Methods:

• Analysis of cyto-/nucleoplasmic localization of native and truncated reflectin variants.
• Investigation of size-dependent nuclear entry of reflectin variants.
• Examination of reflectin A1 interactions with cytoskeletal components like actin and the microtubule organizing center.

Main Results:

• Reflectin variants exhibit distinct cyto-/nucleoplasmic localization preferences.
• Truncated variants replicate localization patterns, suggesting an evolutionary relationship.
• Size-dependent nuclear access provides a model for reflectin entry into Bragg lamellae.
• Reflectin A1 interacts extensively with the cytoskeleton, binding actin and localizing to the MTOC.

Conclusions:

• The cytoskeleton plays a fundamental role in reflectin organization and intracellular transport.
• Findings offer insights into reflectin evolution and biophotonic mechanisms.
• Identified reflectin behaviors provide molecular tools for tunable intracellular transportation.