RRC ID 80726
Author Hara Y, Ichiraku A, Matsuda T, Sakane A, Sasaki T, Nagai T, Horikawa K.
Title High-affinity tuning of single fluorescent protein-type indicators by flexible linker length optimization in topology mutant.
Journal Commun Biol
Abstract Genetically encoded Ca2+ indicators (GECIs) are versatile for live imaging of cellular activities. Besides the brightness and dynamic range of signal change of GECIs, Ca2+ affinity is another critical parameter for successful Ca2+ imaging, as the concentration range of Ca2+ dynamics differs from low nanomolar to sub-millimolar depending on the celltype and organism. However, ultrahigh-affinity GECIs, particularly the single fluorescent protein (1FP)-type, are lacking. Here, we report a simple strategy that increases Ca2+ affinity through the linker length optimization in topology mutants of existing 1FP-type GECIs. The resulting ultrahigh-affinity GECIs, CaMPARI-nano, BGECO-nano, and RCaMP-nano (Kd = 17-25 nM), enable unique biological applications, including the detection of low nanomolar Ca2+ dynamics, highlighting active signaling cells, and multi-functional imaging with other second messengers. The linker length optimization in topology mutants could be applied to other 1FP-type indicators of glutamate and potassium, rendering it a widely applicable technique for modulating indicator affinity.
Volume 7(1)
Pages 705
Published 2024-6-8
DOI 10.1038/s42003-024-06394-0
PII 10.1038/s42003-024-06394-0
PMID 38851844
PMC PMC11162441
MeSH Calcium* / metabolism HEK293 Cells Humans Luminescent Proteins* / chemistry Luminescent Proteins* / genetics Luminescent Proteins* / metabolism Mutation*
Human and Animal Cells HeLa(RCB0007) 293(RCB1637)