RRC ID 60709
Author Bürstenbinder K, Möller B, Plötner R, Stamm G, Hause G, Mitra D, Abel S.
Title The IQD Family of Calmodulin-Binding Proteins Links Calcium Signaling to Microtubules, Membrane Subdomains, and the Nucleus.
Journal Plant Physiol
Abstract Calcium (Ca2+) signaling and dynamic reorganization of the cytoskeleton are essential processes for the coordination and control of plant cell shape and cell growth. Calmodulin (CaM) and closely related calmodulin-like (CML) polypeptides are principal sensors of Ca2+ signals. CaM/CMLs decode and relay information encrypted by the second messenger via differential interactions with a wide spectrum of targets to modulate their diverse biochemical activities. The plant-specific IQ67 DOMAIN (IQD) family emerged as possibly the largest class of CaM-interacting proteins with undefined molecular functions and biological roles. Here, we show that the 33 members of the IQD family in Arabidopsis (Arabidopsis thaliana) differentially localize, using green fluorescent protein (GFP)-tagged proteins, to multiple and distinct subcellular sites, including microtubule (MT) arrays, plasma membrane subdomains, and nuclear compartments. Intriguingly, the various IQD-specific localization patterns coincide with the subcellular patterns of IQD-dependent recruitment of CaM, suggesting that the diverse IQD members sequester Ca2+-CaM signaling modules to specific subcellular sites for precise regulation of Ca2+-dependent processes. Because MT localization is a hallmark of most IQD family members, we quantitatively analyzed GFP-labeled MT arrays in Nicotiana benthamiana cells transiently expressing GFP-IQD fusions and observed IQD-specific MT patterns, which point to a role of IQDs in MT organization and dynamics. Indeed, stable overexpression of select IQD proteins in Arabidopsis altered cellular MT orientation, cell shape, and organ morphology. Because IQDs share biochemical properties with scaffold proteins, we propose that IQD families provide an assortment of platform proteins for integrating CaM-dependent Ca2+ signaling at multiple cellular sites to regulate cell function, shape, and growth.
Volume 173(3)
Pages 1692-1708
Published 2017-3-1
DOI 10.1104/pp.16.01743
PII pp.16.01743
PMID 28115582
PMC PMC5338658
MeSH Arabidopsis / genetics Arabidopsis / metabolism Arabidopsis Proteins / genetics Arabidopsis Proteins / metabolism* Calcium / metabolism Calcium Signaling* Calmodulin / genetics Calmodulin / metabolism Calmodulin-Binding Proteins / genetics Calmodulin-Binding Proteins / metabolism* Cell Nucleus / genetics Cell Nucleus / metabolism* Gene Expression Regulation, Plant Green Fluorescent Proteins / genetics Green Fluorescent Proteins / metabolism Membrane Microdomains / metabolism* Microscopy, Confocal Microtubules / metabolism* Multigene Family Plant Leaves / genetics Plant Leaves / metabolism Plants, Genetically Modified Protein Binding Reverse Transcriptase Polymerase Chain Reaction
IF 6.902
Times Cited 44
Arabidopsis / Cultured plant cells, genes pda06350, pda19553, pda08508, pda12909, pda15315, pda08022, pda14077