Calcium-dependent protein kinase isoforms in Petunia have distinct functions in pollen tube growth, including regulating polarity

Gyeong Mee Yoon; Peter E Dowd; Simon Gilroy; Andrew G McCubbin

doi:10.1105/tpc.105.037135

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Calcium-dependent protein kinase isoforms in Petunia have distinct functions in pollen tube growth, including regulating polarity

Journal article

Open access

Peer reviewed

Calcium-dependent protein kinase isoforms in Petunia have distinct functions in pollen tube growth, including regulating polarity

Gyeong Mee Yoon, Peter E Dowd, Simon Gilroy and Andrew G McCubbin

The Plant cell, Vol.18(4), pp.867-878

04/2006

DOI: https://doi.org/10.1105/tpc.105.037135

Handle:

https://hdl.handle.net/2376/106713

PMCID: PMC1425858

PMID: 16531501

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Abstract

Calcium-Binding Proteins - metabolism

Protein Kinases - metabolism

Recombinant Proteins - metabolism

Petunia - enzymology

Calcium - metabolism

Molecular Sequence Data

DNA Primers

Flowers - growth & development

Petunia - growth & development

Mutagenesis

Isoenzymes - metabolism

Base Sequence

Cell Polarity - physiology

Plant Proteins - metabolism

Enzyme Activation

Calcium is a key regulator of pollen tube growth, but little is known concerning the downstream components of the signaling pathways involved. We identified two pollen-expressed calmodulin-like domain protein kinases from Petunia inflata, CALMODULIN-LIKE DOMAIN PROTEIN KINASE1 (Pi CDPK1) and Pi CDPK2. Transient overexpression or expression of catalytically modified Pi CDPK1 disrupted pollen tube growth polarity, whereas expression of Pi CDPK2 constructs inhibited tube growth but not polarity. Pi CDPK1 exhibited plasma membrane localization most likely mediated by acylation, and we present evidence that suggests this localization is critical to the biological function of this kinase. Pi CDPK2 substantially localized to as yet unidentified internal membrane compartments, and this localization was again, at least partially, mediated by acylation. In contrast with Pi CDPK1, altering the localization of Pi CDPK2 did not noticeably alter the effect of overexpressing this isoform on pollen tube growth. Ca(2+) requirements for Pi CDPK1 activation correlated closely with Ca(2+) concentrations measured in the growth zone at the pollen tube apex. Interestingly, loss of polarity associated with overexpression of Pi CDPK1 was associated with elevated cytosolic Ca(2+) throughout the bulging tube tip, suggesting that Pi CDPK1 may participate in maintaining Ca(2+) homeostasis. These results are discussed in relation to previous models for Ca(2+) regulation of pollen tube growth.

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Title: Calcium-dependent protein kinase isoforms in Petunia have distinct functions in pollen tube growth, including regulating polarity
Creators: Gyeong Mee Yoon - School of Biological Sciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
Peter E Dowd
Simon Gilroy
Andrew G McCubbin
Publication Details: The Plant cell, Vol.18(4), pp.867-878
Academic Unit: Biological Sciences, School of
Publisher: United States
Grant note: F31 GM019381 / NIGMS NIH HHS 5 F31 GM19381-05S1 / NIGMS NIH HHS
Identifiers: 99900547233901842
Language: English
Resource Type: Journal article