A potassium channel-MiRP complex controls neurosensory function in Caenorhabditis elegans

Area of Science:

• Neuroscience
• Molecular Biology
• Ion Channel Physiology

Background:

• MinK-related peptides (MiRPs) are single transmembrane proteins that modulate voltage-gated potassium (K+) channel function.
• Understanding the role of MiRPs and K+ channels in invertebrate nervous systems is essential for comparative physiology.

Purpose of the Study:

• To clone and functionally characterize a novel MiRP beta-subunit (MPS-1) and a K+ channel subunit (KVS-1) from Caenorhabditis elegans.
• To investigate the functional interaction between MPS-1 and KVS-1 in vivo and in vitro.

Main Methods:

• Cloning of MPS-1 and KVS-1 genes from C. elegans.
• RNA interference (RNAi) to inactivate mps-1 and kvs-1 genes.
• Immunohistochemical co-localization studies.
• Heterologous expression in mammalian cells to record K+ currents.

Main Results:

• mps-1 and kvs-1 are expressed in C. elegans chemosensory and mechanosensory neurons, with partial co-localization.
• RNAi inactivation of mps-1 or kvs-1 leads to overlapping neuronal defects, including impaired chemotaxis, mechanotransduction, and locomotion.
• Inactivation of one subunit suppresses the expression of its partner subunit in co-localized cells.
• Co-expression of MPS-1 and KVS-1 in mammalian cells generates a unique potassium current.

Conclusions:

• Potassium currents are fundamental for C. elegans neuronal function.
• MiRPs and K+ channel subunits interact to generate diverse functional properties, a principle conserved across evolution.
• The MPS-1/KVS-1 interaction highlights a conserved mechanism for generating functional diversity in potassium channels.