title: Calmodulin-related CML24 interacts with ATG4b and affects autophagy progression in Arabidopsis.
abstract: Plants encounter environmental stress challenges that are distinct from those of other eukaryotes because of their relative immobility. Therefore, plants may have evolved distinct regulatory mechanisms for conserved cellular functions. Plants, like other eukaryotes, share aspects of both calcium- and calmodulin-based cellular signaling and the autophagic process of cellular renewal. Here, we report a novel function for an Arabidopsis calmodulin-related protein, CML24, and insight into ATG4-regulated autophagy. CML24 interacts with ATG4b in yeast two-hybrid, in vitro pull-down and transient tobacco cell transformation assays. Mutants with missense mutations in CML24 have aberrant ATG4 activity patterns in in vitro extract assays, altered ATG8 accumulation levels, an altered pattern of GFP-ATG8-decorated cellular structures, and altered recovery from darkness-induced starvation. Together, these results support the conclusion that CML24 affects autophagy progression through interactions with ATG4.
authors.affiliation: Biochemistry and Cell Biology, Rice University, Houston, TX, 77005-1892, USA.
authors.forename: Yu-Chang
authors.initials: YC
authors.lastname: Tsai
authors.affiliation: Biochemistry and Cell Biology, Rice University, Houston, TX, 77005-1892, USA.
authors.forename: Yeonjong
authors.initials: Y
authors.lastname: Koo
authors.affiliation: Biochemistry and Cell Biology, Rice University, Houston, TX, 77005-1892, USA.
authors.forename: Nikkí A
authors.initials: NA
authors.lastname: Delk
authors.affiliation: Biochemistry and Cell Biology, Rice University, Houston, TX, 77005-1892, USA.
authors.forename: Bernadette
authors.initials: B
authors.lastname: Gehl
authors.affiliation: Biochemistry and Cell Biology, Rice University, Houston, TX, 77005-1892, USA.
authors.forename: Janet
authors.initials: J
authors.lastname: Braam
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D000071183:Autophagy-Related Proteins; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D057056:Cysteine Proteases / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D049452:Green Fluorescent Proteins; D010957:Plasmids; D020033:Protein Isoforms; D011994:Recombinant Proteins; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D000071183:Autophagy-Related Proteins; D002135:Calcium-Binding Proteins; D020033:Protein Isoforms; D011994:Recombinant Proteins; C106145:TCH2 protein, Arabidopsis; D049452:Green Fluorescent Proteins; C000604990:ATG4b protein, Arabidopsis; C587257:Atg4 protein, Arabidopsis; D057056:Cysteine Proteases