Inositol trisphosphate receptor in higher plants: is it real?

Krinke, Ondřej; Novotná, Zuzana; Valentová, Olga; Martinec, Jan

doi:10.1093/jxb/erl220

Cited by 107 publications

(86 citation statements)

References 127 publications

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“…Subsequent studies identified two additional genes encoding vertebrate IP 3 R (IP 3 R2 and IP 3 R3) and a single gene in invertebrates . It remains far from clear whether plants express related IP 3 R (Krinke et al 2007). These studies established that IP 3 R are unusually large proteins, comprising tetramers of closely-related subunits, each with about 2700 amino acid residues.…”

mentioning

confidence: 99%

IP3 Receptors: Toward Understanding Their Activation

Taylor¹,

Tovey²

2010

Cold Spring Harbor Perspectives in Biology

257

190

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Inositol 1,4,5-trisphosphate receptors (IP 3 R) and their relatives, ryanodine receptors, are the channels that most often mediate Ca 2þ release from intracellular stores. Their regulation by Ca 2þ allows them also to propagate cytosolic Ca 2þ signals regeneratively. This brief review addresses the structural basis of IP 3 R activation by IP 3 and Ca 2þ . IP 3 initiates IP 3 R activation by promoting Ca 2þ binding to a stimulatory Ca 2þ -binding site, the identity of which is unresolved. We suggest that interactions of critical phosphate groups in IP 3 with opposite sides of the clam-like IP 3 -binding core cause it to close and propagate a conformational change toward the pore via the adjacent N-terminal suppressor domain. The pore, assembled from the last pair of transmembrane domains and the intervening pore loop from each of the four IP 3 R subunits, forms a structure in which a luminal selectivity filter and a gate at the cytosolic end of the pore control cation fluxes through the IP 3 R.

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mentioning

confidence: 99%

IP3 Receptors: Toward Understanding Their Activation

Taylor¹,

Tovey²

2010

Cold Spring Harbor Perspectives in Biology

257

190

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“…However, the data available thus far are still insufficient to provide a complete picture of the functions of CaM during pollen tube development. TFP is a potent antipsychotic phenothiazine and has been widely studied in relation to its mode of binding and specific inactivation of CaM (Picton and Steer, 1985;Vandonselaar et al, 1994;Krinke et al, 2007). Therefore, we set up several pharmacological experiments including large-scale proteomic analysis using safe concentrations of TFP in order to extend our knowledge of the involvement of CaM in pollen tube growth.…”

mentioning

confidence: 99%

Combined Proteomic and Cytological Analysis of Ca2+-Calmodulin Regulation inPicea meyeriPollen Tube Growth

Chen

et al. 2008

Plant Physiology

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Ca 2+ -calmodulin (Ca 2+ -CaM) is a critical molecule that mediates cellular functions by interacting with various metabolic and signaling pathways. However, the protein expression patterns and accompanying serial cytological responses in Ca 2+ -CaM signaling deficiency remain enigmatic. Here, we provide a global analysis of the cytological responses and significant alterations in protein expression profiles after trifluoperazine treatment in Picea meyeri, which abrogates Ca 2+ -CaM signaling. Ninety-three differentially displayed proteins were identified by comparative proteomics at different development stages and were assigned to different functional categories closely related to tip growth machinery. The inhibition of Ca 2+ -CaM signaling rapidly induced an increase in extracellular Ca 2+ influx, resulting in dramatically increased cytosolic Ca 2+ concentrations and ultrastructural abnormalities in organelles as the primary responses. Secondary and tertiary alterations included actin filament depolymerization, disrupted patterns of endocytosis and exocytosis, and cell wall remodeling, ultimately resulting in perturbed pollen tube extension. In parallel with these cytological events, time-course experiments revealed that most differentially expressed proteins showed time-dependent quantitative changes (i.e. some signaling proteins and proteins involved in organelle functions and energy production changed first, followed by alterations in proteins related to cytoskeletal organization, secretory pathways, and polysaccharide synthesis). Taken together, Ca 2+ -CaM dysfunction induced serial cytological responses and temporal changes in protein expression profiles, indicating the pivotal role of Ca 2+ -CaM in the regulation of tip growth machinery.

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“…The exact role of DAG and Ins(1,4,5) P 3 need to be investigated in depth owning to the absence of Ins(1,4,5)P 3 sensitive calcium channels 27 and a lack of concrete evidence for DAG-activating plant PKC homologs. Recently, we…”

Section: Localization and Membrane Targetingmentioning

confidence: 99%