Kinase partner protein interacts with the LePRK1 and LePRK2 receptor kinases and plays a role in polarized pollen tube growth

• Published in: The Plant journal : for cell and molecular biology Vol. 42; no. 4; pp. 492 - 503
• Main Authors: Kaothien, P, Ok, S.H, Shuai, B, Wengier, D, Cotter, R, Kelley, D, Kiriakopolos, S, Muschietti, J, McCormick, S
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.05.2005; Blackwell Science; Blackwell Publishing Ltd
• Subjects: actin; Arabidopsis thaliana; Biological and medical sciences; Botany; complementary DNA; cytoplasmic streaming; Flowers - enzymology; Flowers - growth & development; Fundamental and applied biological sciences. Psychology; Gene Expression; gene overexpression; kinase partner protein; Lycopersicon esculentum; Lycopersicon esculentum - enzymology; Lycopersicon esculentum - growth & development; membrane proteins; Molecular Sequence Data; plant morphology; Plant physiology and development; plant proteins; Plant Proteins - metabolism; Plant reproduction; Plants, Genetically Modified; Pollen; pollen tubes; pollen-specific receptor kinase; Protein Binding; protein kinases; Protein Kinases - metabolism; protein phosphorylation; Protein Structure, Tertiary; protein-protein interactions; Proteins; recombinant fusion proteins; Sexual reproduction; Signal Transduction; signaling; Solanum lycopersicum var. lycopersicum; tissue distribution; tomato; tomatoes; Two-Hybrid System Techniques; vacuole; Vegetative and sexual reproduction, floral biology, fructification; yeast two‐hybrid; signaling; Growth; Germination; EC 2.7.1.37; tomato; Vacuole; Pollen tube; Arabidopsis thaliana; actin; Complementary DNA; Gene; Cruciferae; Dicotyledones; Angiospermae; Lycopersicon esculentum; yeast two-hybrid; Spermatophyta; Pollen; cytoplasmic streaming; Solanaceae
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313X.2005.02388.x

The pollen-specific receptor kinases LePRK1 and LePRK2 have localization and expression profiles that strongly suggest they play roles in pollen germination and tube growth. To identify downstream components of LePRK signaling, we used their cytoplasmic domains (CDs) as baits in yeast two-hybrid screens of a tomato pollen cDNA library. A pollen-specific protein we named kinase partner protein (KPP) interacted with the CDs of both LePRK1 and LePRK2 in yeast and in an in vitro pull-down assay, and with LePRK2 in a co-immunoprecipitation assay. KPP is a peripheral membrane protein and is phosphorylated in pollen. Pollen tubes over-expressing KPP developed balloon-like tips with abnormal cytoplasmic streaming and F-actin arrangements and plants over-expressing KPP exhibited impaired transmission of the transgene through the male. KPP-like genes are found only in plants; the 14 family members in Arabidopsis thaliana exhibit diverse expression patterns and potentially play roles in signaling pathways in other tissues.