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TRPML2 and the evolution of mucolipins
Emma N Flores1, Jaime García-Añoveros
1Departments of Anesthesiology, Physiology and Neurology, Northwestern University Institute for Neuroscience, Chicago, IL 60611, USA. enflores@nothwestern.edu.
Advances in Experimental Medicine and Biology
|February 4, 2011
Summary
TRPML2, a mucolipin ion channel, exhibits basal activity and is permeable to calcium, sodium, and iron. Its localization in endolysosomes and potential roles in calcium signaling and cell surface regulation are suggested.
Area of Science:
- Molecular Biology
- Cell Biology
- Ion Channel Physiology
Background:
- TRPML2 (Mucolipin 2) is a member of the TRPML ion channel family.
- Its precise function remains largely unknown, but it exhibits constitutive activity in mammalian cells with specific mutations.
Purpose of the Study:
- To characterize the biophysical properties and cellular localization of TRPML2.
- To explore the evolutionary context of the TRPML2 gene and its relatives.
Main Methods:
- Heterologous expression in Drosophila S2 cells and mammalian cells.
- Electrophysiological recordings to determine channel activity and ion permeability.
- Subcellular localization studies using immunofluorescence.
- Bioinformatic and evolutionary analysis of TRPML gene family.
Main Results:
- TRPML2 forms inwardly rectifying channels permeable to Ca2+, Na+, and Fe2+.
- The channel is localized to lysosomes, late endosomes, recycling endosomes, and the plasma membrane.
- TRPML2 expression is suggested in lymphoid cells.
- Evolutionary analysis reveals conserved gene linkage between TRPML2 and TRPML3 in tetrapods.
Conclusions:
- TRPML2's properties suggest roles in endolysosomal calcium release and calcium-dependent cellular processes.
- Its plasma membrane localization may be regulated by endocytosis and exocytosis.
- The conserved linkage of TRPML2 and TRPML3 implies interdependent regulation.
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