title: A pollen-specific calmodulin-binding protein, NPG1, interacts with putative pectate lyases.
abstract: Previous genetic studies have revealed that a pollen-specific calmodulin-binding protein, No Pollen Germination 1 (NPG1), is required for pollen germination. However, its mode of action is unknown. Here we report direct interaction of NPG1 with pectate lyase-like proteins (PLLs). A truncated form of AtNPG1 lacking the N-terminal tetratricopeptide repeat 1 (TPR1) failed to interact with PLLs, suggesting that it is essential for NPG1 interaction with PLLs. Localization studies with AtNPG1 fused to a fluorescent reporter driven by its native promoter revealed its presence in the cytosol and cell wall of the pollen grain and the growing pollen tube of plasmolyzed pollen. Together, our data suggest that the function of NPG1 in regulating pollen germination is mediated through its interaction with PLLs, which may modify the pollen cell wall and regulate pollen tube emergence and growth.
authors.affiliation: 1] Department of Biology, Program in Molecular Plant Biology, Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA [2].
authors.forename: Sung-Bong
authors.initials: SB
authors.lastname: Shin
authors.affiliation: 1] Department of Biology, Program in Molecular Plant Biology, Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA [2].
authors.forename: Maxim
authors.initials: M
authors.lastname: Golovkin
authors.affiliation: Department of Biology, Program in Molecular Plant Biology, Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Anireddy S N
authors.initials: AS
authors.lastname: Reddy
mesh_terms: D002147:Calmodulin / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D002473:Cell Wall / Q000378:metabolism; D004396:Coloring Agents / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D018525:Germination / Q000502:physiology*; D011058:Pollen / Q000378:metabolism*; D054817:Pollination / Q000502:physiology; D011133:Polysaccharide-Lyases / Q000378:metabolism*
chemical_list: D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D002352:Carrier Proteins; D004396:Coloring Agents; D011133:Polysaccharide-Lyases; C023911:pectate lyase