Cooperation of two distinct coupling proteins creates chemosensory network connections.

Although it is appreciated that bacterial chemotaxis systems rely on coupling, also called scaffold, proteins to both connect input receptors with output kinases and build interkinase connections that allow signal amplification, it is not yet clear why many systems use more than one coupling protein. We examined the distinct functions for multiple coupling proteins in the bacterial chemotaxis system of Helicobacter pylori, which requires two nonredundant coupling proteins for chemotaxis: CheW and CheV1, a hybrid of a CheW and a phosphorylatable receiver domain. We report that CheV1 and CheW have largely redundant abilities to interact with chemoreceptors and the CheA kinase, and both similarly activated CheA's kinase activity. We discovered, however, that they are not redundant for formation of the higher order chemoreceptor arrays that are known to form via CheA-CheW interactions. In support of this possibility, we found that CheW and CheV1 interact with each other and with CheA independent of the chemoreceptors. Therefore, it seems that some microbes have modified array formation to require CheW and CheV1. Our data suggest that multiple coupling proteins may be used to provide flexibility in the chemoreceptor array formation.

Helicobacter pylori CheZ(HP) and ChePep form a novel chemotaxis-regulatory complex distinct from the core chemotaxis signaling proteins and the flagellar motor.

Chemotaxis is important for Helicobacter pylori to colonize the stomach. Like other bacteria, H. pylori uses chemoreceptors and conserved chemotaxis proteins to phosphorylate the flagellar rotational response regulator, CheY, and modulate the flagellar rotational direction. Phosphorylated CheY is returned to its non-phosphorylated state by phosphatases such as CheZ. In previously studied cases, chemotaxis phosphatases localize to the cellular poles by interactions with either the CheA chemotaxis kinase or flagellar motor proteins. We report here that the H. pylori CheZ, CheZ(HP), localizes to the poles independently of the flagellar motor, CheA, and all typical chemotaxis proteins. Instead, CheZ(HP) localization depends on the chemotaxis regulatory protein ChePep, and reciprocally, ChePep requires CheZ(HP) for its polar localization. We furthermore show that these proteins interact directly. Functional domain mapping of CheZ(HP) determined the polar localization motif lies within the central domain of the protein and that the protein has regions outside of the active site that participate in chemotaxis. Our results suggest that CheZ(HP) and ChePep form a distinct complex. These results therefore suggest the intriguing idea that some phosphatases localize independently of the other chemotaxis and motility proteins, possibly to confer unique regulation on these proteins' activities.

Estudio anatómico del orificio esfenopalatino / Sphenopalatinum foramen: an anatomical study

Introducción: La localización de la arteria esfenopalatina es fundamental en el tratamiento endoscópico de la epistaxis posterior severa. El orificio esfenopalatino, que le da salida, es variable en ubicación y relaciones anatómicas. Objetivo: Realizar un estudio descriptivo osteológico de la región del orificio esfenopalatino, describiendo la anatomía de dicha región, tamaño, localización, relaciones con cornetes y coanas, así como la existencia de orificios accesorios. Material y métodos: La exploración y el estudio anatómico de la zona se llevó a cabo en 32 hemicráneos humanos. Resultados: La localización más frecuente del orificio esfenopalatino resultó la transición entre el meato medio y superior en el 56,25%, 18 especímenes, seguido del meato superior, 37,5% (12 hemicráneos) y solamente en 2 casos el orificio se abría exclusivamente en meato medio. En el 50% de los casos encontramos la existencia de orificios accesorios, cuya localización más frecuente fue inferior al orificio en el meato medio. La cresta etmoidal se encontraba presente en todos los cráneos estudiados, produciendo un resalte anterior en el orificio esfenopalatino. Conclusión: Existen variaciones anatómicas en el orificio esfenopalatino en cuanto a localización, número y relaciones anatómicas que modificarán la entrada de la arteria esfenopalatina y sus ramas en la fosa nasal. Habiendo encontrado una marca constante localizadora del orificio esfenopalatino, la cresta etmoidal, situada en el borde anterior del orificio (AU)

Introduction: The position of the sphenopalatine artery is essential for the endoscopic treatment of severe posterior epistaxis. This artery passes through its own foramen, which has awide range of locations and anatomic relations. Objective: To carry out a descriptive osteological study on the sphenopalatine foramen area. Its anatomy, size, position and relations with turbinates and choanae are described, as well as the existence of accessory foramina. Material and methods: Exploration and anatomical study was carried out in 32 human hemicrania. Results: The area between middle and superior meatus was considered the most common location of the sphenopalatine foramen in 56.24% of the cases (18 specimens), followed by the superior meatus, with 37.5% (12 hemi-skulls). The foramen was located in middle meatus injust two cases. We found accessory foramina in 50% of the cases, most commonly positioned below the middle meatus. The ethmoidal crest appeared in every skull, producing an anteriorosseous projection on the sphenopalatine foramen. Conclusion: There are variations in position, number and anatomic relations that may cause changes in the sphenopalatine artery orifice and its branches into the nasal fossa. The ethmoidal crest, located on the anterior side of the sphenopalatine foramen, can be considered a permanent landmark to find the foramen (AU)

[Sphenopalatinum foramen: an anatomical study]. / Estudio anatómico del orificio esfenopalatino.

INTRODUCTION: The position of the sphenopalatine artery is essential for the endoscopic treatment of severe posterior epistaxis. This artery passes through its own foramen, which has a wide range of locations and anatomic relations. OBJECTIVE: To carry out a descriptive osteological study on the sphenopalatine foramen area. Its anatomy, size, position and relations with turbinates and choanae are described, as well as the existence of accessory foramina. MATERIAL AND METHODS: Exploration and anatomical study was carried out in 32 human hemi-crania. RESULTS: The area between middle and superior meatus was considered the most common location of the sphenopalatine foramen in 56.24% of the cases (18 specimens), followed by the superior meatus, with 37.5% (12 hemi-skulls). The foramen was located in middle meatus in just two cases. We found accessory foramina in 50% of the cases, most commonly positioned below the middle meatus. The ethmoidal crest appeared in every skull, producing an anterior osseous projection on the sphenopalatine foramen. CONCLUSION: There are variations in position, number and anatomic relations that may cause changes in the sphenopalatine artery orifice and its branches into the nasal fossa. The ethmoidal crest, located on the anterior side of the sphenopalatine foramen, can be considered a permanent landmark to find the foramen.