Calcium homeostasis in crustaceans: subcellular Ca dynamics.

Area of Science:

• Crustacean physiology
• Cellular biology
• Biochemistry

Background:

• The crustacean molting cycle involves significant cuticle renewal and remineralization.
• Calcium (Ca2+) transport is crucial for these processes and is regulated by specific proteins common to eukaryotes.
• Transporting epithelia in crustaceans (gills, hepatopancreas, antennal gland) are key sites for Ca2+ regulation.

Purpose of the Study:

• To review current knowledge on how crustacean transporting epithelia facilitate mass transcellular Ca2+ movement.
• To understand the mechanisms preventing cytotoxicity during high Ca2+ flux.
• To compare Ca2+ transport proteins (NCX, PMCA) across different species and epithelia.

Main Methods:

• Review of existing in vitro and organismic research, primarily focusing on the intermolt stage.
• Analysis of plasma membrane proteins (NCX, PMCA) involved in Ca2+ transport.
• Integration of extracellular exchange with intracellular sequestration mechanisms (ER/SR, mitochondria).

Main Results:

• Epithelial Ca2+ transport involves coordinated action of apical and basolateral proteins like NCX and PMCA.
• Mechanisms differ between aquatic species with varying osmotic backgrounds and among different crustacean epithelia.
• Intracellular organelles (ER/SR, mitochondria) play a role in sequestering Ca2+.

Conclusions:

• Crustacean molting provides a model for studying Ca2+ transport regulation in eukaryotic cells.
• Understanding these transport systems is vital for managing Ca2+ homeostasis and preventing toxicity.
• Future Ca2+ imaging techniques promise enhanced spatial and temporal resolution of Ca2+ dynamics in subcellular compartments.