Calcium-dependent protein kinases regulate polarized tip growth in pollen tubes.

Calcium signals are critical for the regulation of polarized growth in many eukaryotic cells, including pollen tubes and neurons. In plants, the regulatory pathways that code and decode Ca(2+) signals are poorly understood. In Arabidopsis thaliana, genetic evidence presented here indicates that pollen tube tip growth involves the redundant activity of two Ca(2+)-dependent protein kinases (CPKs), isoforms CPK17 and -34.

A distinct endosomal Ca2+/Mn2+ pump affects root growth through the secretory process.

Ca(2+) is required for protein processing, sorting, and secretion in eukaryotic cells, although the particular roles of the transporters involved in the secretory system of plants are obscure. One endomembrane-type Ca-ATPase from Arabidopsis (Arabidopsis thaliana), AtECA3, diverges from AtECA1, AtECA2, and AtECA4 in protein sequence; yet, AtECA3 appears similar in transport activity to the endoplasmic reticulum (ER)-bound AtECA1. Expression of AtECA3 in a yeast (Saccharomyces cerevisiae) mutant defective in its endogenous Ca(2+) pumps conferred the ability to grow on Ca(2+)-depleted medium and tolerance to toxic levels of Mn(2+).

The ACA10 Ca2+-ATPase regulates adult vegetative development and inflorescence architecture in Arabidopsis.

The Arabidopsis (Arabidopsis thaliana) compact inflorescence (cif) genotype causes altered adult vegetative development and a reduction in elongation of inflorescence internodes resulting in formation of floral clusters. The cif trait requires both a recessive mutation, cif1, and the activity of a naturally occurring dominant allele of an unlinked gene, CIF2(D). We show here that the pseudoverticillata mutation is allelic with cif1 and that the product of the CIF1 gene is ACA10, a member of the large family of P-type Ca(2+)-ATPases found in higher plants.

A cyclic nucleotide-gated channel is essential for polarized tip growth of pollen.

Ion signals are critical to regulating polarized growth in many cell types, including pollen in plants and neurons in animals. Genetic evidence presented here indicates that pollen tube growth requires cyclic nucleotide-gated channel (CNGC) 18. CNGCs are nonspecific cation channels found in plants and animals and have well established functions in excitatory signal transduction events in animals.

Cervical transforaminal epidural steroid injections: more dangerous than we think?

Study Design: Survey/case series.

Objective: To survey pain physicians about neurologic infarctions following cervical transforaminal epidural steroid injections (TF-ESIs).

Summary Of Background Data: Cervical TF-ESIs are commonly performed in patients with cervical radiculopathy, although there are no randomized controlled studies supporting their efficacy.

A plant plasma membrane Ca2+ pump is required for normal pollen tube growth and fertilization.

Ca(2+) signals are thought to play important roles in plant growth and development, including key aspects of pollen tube growth and fertilization. The dynamics of a Ca(2+) signal are largely controlled by influx (through channels) and efflux (through pumps and antiporters). The Arabidopsis genome encodes 14 Ca(2+) pumps, 10 of which belong to a family of autoinhibited Ca(2+) ATPases (ACA) that are predicted to be activated by Ca(2+)/calmodulin.

Subcellular targeting of nine calcium-dependent protein kinase isoforms from Arabidopsis.

Calcium-dependent protein kinases (CDPKs) are specific to plants and some protists. Their activation by calcium makes them important switches for the transduction of intracellular calcium signals. Here, we identify the subcellular targeting potentials for nine CDPK isoforms from Arabidopsis, as determined by expression of green fluorescent protein (GFP) fusions in transgenic plants.