A PTP1B-Cdk3 Signaling Axis Promotes Cell Cycle Progression of Human Glioblastoma Cells through an Rb-E2F Dependent Pathway.

PTP1B plays a key role in developing different types of cancer. However, the molecular mechanism underlying this effect is unclear. To identify molecular targets of PTP1B that mediate its role in tumorigenesis, we undertook a SILAC-based phosphoproteomic approach, which allowed us to identify Cdk3 as a novel PTP1B substrate. Substrate trapping experiments and docking studies revealed stable interactions between the PTP1B catalytic domain and Cdk3. In addition, we observed that PTP1B dephosphorylates Cdk3 at tyrosine residue 15 in vitro and interacts with it in human glioblastoma cells. Next, we found that pharmacological inhibition of PTP1B or its depletion with siRNA leads to cell cycle arrest with diminished activity of Cdk3, hypophosphorylation of Rb, and the downregulation of E2F target genes Cdk1, Cyclin A, and Cyclin E1. Finally, we observed that the expression of a constitutively active Cdk3 mutant bypasses the requirement of PTP1B for cell cycle progression and expression of E2F target genes. These data delineate a novel signaling pathway from PTP1B to Cdk3 required for efficient cell cycle progression in an Rb-E2F dependent manner in human GB cells.

LPA1 Receptor Promotes Progesterone Receptor Phosphorylation through PKCα in Human Glioblastoma Cells.

Lysophosphatidic acid (LPA) induces a wide range of cellular processes and its signaling is increased in several cancers including glioblastoma (GBM), a high-grade astrocytoma, which is the most common malignant brain tumor. LPA1 receptor is expressed in GBM cells and its signaling pathways activate protein kinases C (PKCs). A downstream target of PKC, involved in GBM progression, is the intracellular progesterone receptor (PR), which can be phosphorylated by this enzyme, increasing its transcriptional activity. Interestingly, in GBM cells, PKCα isotype translocates to the nucleus after LPA stimulation, resulting in an increase in PR phosphorylation. In this study, we determined that LPA1 receptor activation induces protein-protein interaction between PKCα and PR in human GBM cells; this interaction increased PR phosphorylation in serine400. Moreover, LPA treatment augmented VEGF transcription, a known PR target. This effect was blocked by the PR selective modulator RU486; also, the activation of LPA1/PR signaling promoted migration of GBM cells. Interestingly, using TCGA data base, we found that mRNA expression of LPAR1 increases according to tumor malignancy and correlates with a lower survival in grade III astrocytomas. These results suggest that LPA1/PR pathway regulates GBM progression.

Antimicrobial profile of Acinetobacter baumannii at a tertiary hospital in Honduras: a cross-sectional analysis.

Acinetobacter baumannii is considered to be a worldwide threat to public health due to its high antimicrobial resistance rates and the severe infections it can cause. Little is known about this pathogen's resistance in Central America. This report aims to describe the antimicrobial resistance profile of A. baumannii at a tertiary hospital in Honduras. The cross-sectional analysis was conducted at the tertiary care laboratory hospital in San Pedro Sula in 2015 - 2017. A total of 113 consecutive microbiological reports were analyzed, comprising 100 individuals from whom A. baumannii was isolated. Epidemiological and microbiological data, including the isolation setting and patient information, were recorded. Prevalence of multi-drug and extensive-drug resistance was assessed according to international standards. The median age of individuals was 22 years (2 - 35 years); female was the predominant gender (53%). The hospital's pediatric wards had the highest number of isolates (n = 48). The most frequent specimen from which A. baumannii was isolated was skin and soft tissue (n = 39). Resistance to carbapenems was reported to be 40.7% among the isolates (n = 46); multi-drug resistant, 35.4% (n = 40); and extensively-drug resistant, 7.1% (n = 8). This report reveals the threat of this pathogen to public health in Honduras and appeals for antibiotic stewardship programs throughout Central America.

Acinetobacter baumannii se considera como una amenaza mundial para la salud pública debido a sus tasas elevadas de resistencia a los antimicrobianos y a las infecciones graves que puede causar. Es poco lo que se conoce acerca de la resistencia de este agente patógeno en Centroamérica, por lo que el propósito de este informe es describir el perfil de resistencia a los antimicrobianos de A. baumannii mediante un estudio llevado a cabo en un hospital de atención terciaria en Honduras. Entre el 2015 y el 2017, se realizó un análisis transversal en el laboratorio de atención terciaria en el Instituto Hondureño de Seguridad Social en San Pedro Sula. Se analizó un total de 113 informes de análisis microbiológicos consecutivos, en los que las cepas aisladas de A. Baumannii provenían de un grupo de 100 personas. Se registraron los datos epidemiológicos y microbianos, así como el entorno de aislamiento y la información del paciente. La prevalencia de la multirresistencia y la resistencia extensa se evaluó con base en las normas internacionales. La mediana de edad de las personas fue de 22 años (intervalo: de 2 a 35 años de edad) y predominó el sexo femenino (53%). Las salas de pediatría del hospital presentaron el número más alto de cepas aisladas (n = 48). La piel y el tejido blando (n = 39) fueron las muestras más frecuente de las cuales se aisló la cepa A. Baumannii. Se notificó 40,7% de resistencia a los fármacos carbapenémicos en las cepas aisladas (n = 46); 35,4% de multirresistencia (n = 40); y 7,1% de resistencia extensa (n = 8). Este informe pone en evidencia la amenaza que este agente patógeno representa para la salud pública en Honduras. Asimismo, sirve para alertar a los programas de optimización del uso de antibióticos en Centroamérica.

Acinetobacter baumannii é considerado uma ameaça à saúde pública em todo o mundo devido às suas altas taxas de resistência antimicrobiana e às graves infecções que pode causar. Sabe-se pouco sobre a resistência deste patógeno na América Central. Este artigo visa descrever o perfil de resistência antimicrobiana de A. baumannii em um hospital terciário em Honduras. Realizamos uma análise transversal no hospital terciário de San Pedro Sula, de 2015 a 2017. Analisamos um total de 113 laudos microbiológicos consecutivos, que envolveram 100 pessoas das quais foi isolado A. baumannii. Registramos dados epidemiológicos e microbiológicos, incluindo o ambiente onde foi feito o isolamento e informações sobre os pacientes. Avaliamos a prevalência de resistência a múltiplos fármacos e resistência extensiva, de acordo com padrões internacionais. A idade mediana dos participantes foi de 22 anos (intervalo, 2 a 35 anos); a maioria dos participantes foi do sexo feminino (53%). As enfermarias pediátricas do hospital tiveram o maior número de isolados (n = 48). A pele e os tecidos moles foram os espécimes mais frequentes de isolamento de A. baumannii (n = 39). A resistência aos carbapenens foi constatada em 40,7% dos isolados (n = 46), a resistência a múltiplos fármacos esteve presente em 35,4% (n = 40) e a resistência extensiva em 7,1% (n = 8). Este artigo revela a ameaça que este patógeno representa à saúde pública em Honduras e faz um apelo pela implantação de programas de gestão do uso de antibióticos em toda a América Central.

Antimicrobial profile of Acinetobacter baumannii at a tertiary hospital in Honduras: a cross-sectional analysis

[ABSTRACT]. Acinetobacter baumannii is considered to be a worldwide threat to public health due to its high antimicrobial resistance rates and the severe infections it can cause. Little is known about this pathogen’s resistance in Central America. This report aims to describe the antimicrobial resistance profile of A. baumannii at a tertiary hospital in Honduras. The cross-sectional analysis was conducted at the tertiary care laboratory hospital in San Pedro Sula in 2015 – 2017. A total of 113 consecutive microbiological reports were analyzed, comprising 100 individuals from whom A. baumannii was isolated. Epidemiological and microbiological data, including the isolation setting and patient information, were recorded. Prevalence of multi-drug and extensive-drug resistance was assessed according to international standards. The median age of individuals was 22 years (2 – 35 years); female was the predominant gender (53%). The hospital’s pediatric wards had the highest number of isolates (n = 48). The most frequent specimen from which A. baumannii was isolated was skin and soft tissue (n = 39). Resistance to carbapenems was reported to be 40.7% among the isolates (n = 46); multi-drug resistant, 35.4% (n = 40); and extensively-drug resistant, 7.1% (n = 8). This report reveals the threat of this pathogen to public health in Honduras and appeals for antibiotic stewardship programs throughout Central America.

[RESUMEN]. Acinetobacter baumannii se considera como una amenaza mundial para la salud pública debido a sus tasas elevadas de resistencia a los antimicrobianos y a las infecciones graves que puede causar. Es poco lo que se conoce acerca de la resistencia de este agente patógeno en Centroamérica, por lo que el propósito de este informe es describir el perfil de resistencia a los antimicrobianos de A. baumannii mediante un estudio llevado a cabo en un hospital de atención terciaria en Honduras. Entre el 2015 y el 2017, se realizó un análisis transversal en el laboratorio de atención terciaria en el Instituto Hondureño de Seguridad Social en San Pedro Sula. Se analizó un total de 113 informes de análisis microbiológicos consecutivos, en los que las cepas aisladas de A. Baumannii provenían de un grupo de 100 personas. Se registraron los datos epidemiológicos y microbianos, así como el entorno de aislamiento y la información del paciente. La prevalencia de la multirresistencia y la resistencia extensa se evaluó con base en las normas internacionales. La mediana de edad de las personas fue de 22 años (intervalo: de 2 a 35 años de edad) y predominó el sexo femenino (53%). Las salas de pediatría del hospital presentaron el número más alto de cepas aisladas (n = 48). La piel y el tejido blando (n = 39) fueron las muestras más frecuente de las cuales se aisló la cepa A. Baumannii. Se notificó 40,7% de resistencia a los fármacos carbapenémicos en las cepas aisladas (n = 46); 35,4% de multirresistencia (n = 40); y 7,1% de resistencia extensa (n = 8). Este informe pone en evidencia la amenaza que este agente patógeno representa para la salud pública en Honduras. Asimismo, sirve para alertar a los programas de optimización del uso de antibióticos en Centroamérica.

[RESUMO]. Acinetobacter baumannii é considerado uma ameaça à saúde pública em todo o mundo devido às suas altas taxas de resistência antimicrobiana e às graves infecções que pode causar. Sabe-se pouco sobre a resistência deste patógeno na América Central. Este artigo visa descrever o perfil de resistência antimicrobiana de A. baumannii em um hospital terciário em Honduras. Realizamos uma análise transversal no hospital terciário de San Pedro Sula, de 2015 a 2017. Analisamos um total de 113 laudos microbiológicos consecutivos, que envolveram 100 pessoas das quais foi isolado A. baumannii. Registramos dados epidemiológicos e microbiológicos, incluindo o ambiente onde foi feito o isolamento e informações sobre os pacientes. Avaliamos a prevalência de resistência a múltiplos fármacos e resistência extensiva, de acordo com padrões internacionais. A idade mediana dos participantes foi de 22 anos (intervalo, 2 a 35 anos); a maioria dos participantes foi do sexo feminino (53%). As enfermarias pediátricas do hospital tiveram o maior número de isolados (n = 48). A pele e os tecidos moles foram os espécimes mais frequentes de isolamento de A. baumannii (n = 39). A resistência aos carbapenens foi constatada em 40,7% dos isolados (n = 46), a resistência a múltiplos fármacos esteve presente em 35,4% (n = 40) e a resistência extensiva em 7,1% (n = 8). Este artigo revela a ameaça que este patógeno representa à saúde pública em Honduras e faz um apelo pela implantação de programas de gestão do uso de antibióticos em toda a América Central.

p21 Activated kinase 1: Nuclear activity and its role during DNA damage repair.

p21-activated kinase 1 (PAK1) is a serine/threonine kinase activated by the small GTPases Rac1 and Cdc42. It is located in the chromosome 11q13 and is amplified and/or overexpressed in several human cancer types including 25-30% of breast tumors. This enzyme plays a pivotal role in the control of a number of fundamental cellular processes by phosphorylating its downstream substrates. In addition to its role in the cytoplasm, it is well documented that PAK1 also plays crucial roles in the nucleus participating in mitotic events and gene expression through its association and/or phosphorylation of several transcription factors, transcriptional co-regulators and cell cycle-related proteins, including Aurora kinase A (AURKA), polo-like kinase 1 (PLK1), the forkhead transcription factor (FKHR), estrogen receptor α (ERα), and Snail. More recently, PAK signaling has emerged as a component of the DNA damage response (DDR) as PAK1 activity influences the cellular sensitivity to ionizing radiation and promotes the expression of several genes involved in the Fanconi Anemia/BRCA pathway. This review will focus on the nuclear functions of PAK1 and its role in the regulation of DNA damage repair.

Citología aspirativa con aguja fina transbroncoscópica en lesiones endobronquiales / Transbronchoscopic Needle Aspiration Cytology in Endobronchial Lesions

Introducción: el diagnóstico temprano del cáncer del pulmón es de vital importancia para tratar de disminuir la mortalidad por esta enfermedad (que es muy alta). La citología aspirativa con aguja fina transbronscoscópica juega un papel significativo en el diagnóstico y estadiamiento del carcinoma broncógeno.Objetivo: determinar la eficacia de la citología aspirativa con aguja fina transbroncoscópica en lesiones tumorales endobronquiales.Métodos: se realizó un estudio descriptivo, de corte transversal prospectivo, en pacientes a los que se les realizó citología aspirativa con aguja fina transbroncoscópica en lesiones endobronquiales, en el servicio de Neumología del Hospital Hermanos Ameijeiras, en el periodo comprendido entre enero de 2015 a enero de 2016. Se tomó en cuenta como variables la ubicación del tumor endobronquial, el diagnóstico citológico, el tipo de lesión tumoral y las complicaciones.Resultados: predominó el sexo masculino, el rango de edad mayor de 60 años y el color de piel blanca. Las lesiones fueron más frecuentes del lado derecho, fue más eficaz el proceder cuando los tumores se ubicaron hacia los bronquios inferiores, y se describían como masa tumoral o tipo mixta. La sensibilidad diagnóstica fue de aproximadamente 70 por ciento. El número de complicaciones fue muy bajo.Conclusiones: la biopsia aspirativa con aguja fina de tumores endobronquiales tiene un alto rendimiento diagnóstico con un número bajo de complicaciones(AU)

Introduction: Early diagnosis of lung cancer is vital in trying to reduce mortality from this disease (which is very high). Transbronscoscopic needle aspiration cytology plays a significant role in the diagnosis and staging of bronchogenic carcinoma.Objective: Determine the efficacy of transbronchoscopic needle aspiration cytology in endobronchial tumor lesions.Methods: A prospective, cross-sectional, descriptive study was performed in patients undergoing transbronchoscopic needle aspiration cytology in endobronchial lesions, in the Pulmonology Department of Hermanos Ameijeiras Hospital, from January 2015 to January 2016. The location of the endobronchial tumor, the cytologic diagnosis, the type of tumor lesion and the complications were taken into account as variables.Results: Age range was greater than 60, male gender and white skin color predominated. The lesions were more frequent on the right side, the procedure was more effective when the tumors were located towards the lower bronchi, and they were described as tumor mass or mixed type. The diagnostic sensitivity was approximately 70 percent. The number of complications was very low.Conclusions: Spinal biopsy with fine needle of endobronchial tumors has a high diagnostic yield with a low number of complications(AU)

Citología aspirativa con aguja fina transbroncoscópica en lesiones endobronquiales / Transbronchoscopic Needle Aspiration Cytology in Endobronchial Lesions

Introducción: el diagnóstico temprano del cáncer del pulmón es de vital importancia para tratar de disminuir la mortalidad por esta enfermedad (que es muy alta). La citología aspirativa con aguja fina transbronscoscópica juega un papel significativo en el diagnóstico y estadiamiento del carcinoma broncógeno. Objetivo: determinar la eficacia de la citología aspirativa con aguja fina transbroncoscópica en lesiones tumorales endobronquiales. Métodos: se realizó un estudio descriptivo, de corte transversal prospectivo, en pacientes a los que se les realizó citología aspirativa con aguja fina transbroncoscópica en lesiones endobronquiales, en el servicio de Neumología del Hospital Hermanos Ameijeiras, en el periodo comprendido entre enero de 2015 a enero de 2016. Se tomó en cuenta como variables la ubicación del tumor endobronquial, el diagnóstico citológico, el tipo de lesión tumoral y las complicaciones. Resultados: predominó el sexo masculino, el rango de edad mayor de 60 años y el color de piel blanca. Las lesiones fueron más frecuentes del lado derecho, fue más eficaz el proceder cuando los tumores se ubicaron hacia los bronquios inferiores, y se describían como masa tumoral o tipo mixta. La sensibilidad diagnóstica fue de aproximadamente 70 por ciento. El número de complicaciones fue muy bajo. Conclusiones: la biopsia aspirativa con aguja fina de tumores endobronquiales tiene un alto rendimiento diagnóstico con un número bajo de complicaciones(AU)

Introduction: Early diagnosis of lung cancer is vital in trying to reduce mortality from this disease (which is very high). Transbronscoscopic needle aspiration cytology plays a significant role in the diagnosis and staging of bronchogenic carcinoma. Objective: Determine the efficacy of transbronchoscopic needle aspiration cytology in endobronchial tumor lesions. Methods: A prospective, cross-sectional, descriptive study was performed in patients undergoing transbronchoscopic needle aspiration cytology in endobronchial lesions, in the Pulmonology Department of Hermanos Ameijeiras Hospital, from January 2015 to January 2016. The location of the endobronchial tumor, the cytologic diagnosis, the type of tumor lesion and the complications were taken into account as variables. Results: Age range was greater than 60, male gender and white skin color predominated. The lesions were more frequent on the right side, the procedure was more effective when the tumors were located towards the lower bronchi, and they were described as tumor mass or mixed type. The diagnostic sensitivity was approximately 70 percent The number of complications was very low. Conclusions: Spinal biopsy with fine needle of endobronchial tumors has a high diagnostic yield with a low number of complications(AU)

CAREX Nicaragua and Panama: Worker exposures to carcinogenic substances and pesticides.

This study provides data on numbers of workers exposed at work to selected carcinogens and pesticides in Nicaragua (35 substances) and Panama (31), based on a modification of the CAREX data system. Population censuses provided industry- and sex-specific workforce numbers. The activity- and sex-specific proportions of exposed workers were estimated by experts from governmental agencies, workers' organizations, and employers' representatives. Finally, the numbers of those occupied in each activity/sex category were multiplied by the proportions of those exposed in the same categories, yielding numbers of those exposed in these categories for each agent. The study revealed high proportions (> 9%) of occupationally exposed workers in both countries for solar radiation and diesel engine emissions; environmental tobacco smoke in Panama; and some pesticides in Nicaragua. A high proportion of exposed was found for men for lead (12%), silica dust (10%), and hexavalent chromium (10%) in Panama.

Novel structural and functional findings of the ehFLN protein from Entamoeba histolytica.

The ehFLN protein (previously known as EhABP-120) is the first filamin to be identified in the parasitic protozoan Entamoeba histolytica. Filamins are a family of cross-linking actin-binding proteins that organize filamentous actin in networks and stress fibers. It has been reported that filamins of different organisms directly interact with more than 30 cellular proteins and some PPIs. The biochemical consequences of such interactions may have either positive or negative effects on the cross-linking function. Besides, filamins form a link between cytoskeleton and plasma membrane. In this work, the ehFLN protein was biochemically characterized; amoebae filamin was found to associate with both PA and PI(3)P in vitro, new lipid targets for a member of the filamins. By molecular modeling analysis and protein-lipid overlay assays, K-609, 709, and 710 were determined to be essential for the PA-ehFLN1 complex stability. Also, the integrity of the 4th repeat of ehFLN is essential to keep interaction with the PI(3)P. Transfected trophozoites that overexpressed the d100, d50NH(2), and d50COOH regions of ehFLN1 displayed both increased motility and chemotactic response to TYI-S-33 media. Together, these results suggest that short regions of ehFLN are involved in signaling events that, in cooperation with phosphatidic acid, EhPLD2 and EhPI3K, could promote cell motility.

EhGEF2, a Dbl-RhoGEF from Entamoeba histolytica has atypical biochemical properties and participates in essential cellular processes.

Dbl proteins are a family of factors that exchange the guanine nucleotide which promote the activation of Rho small GTPases. This paper reports the molecular, structural, biochemical and functional characterization of EhGEF2, a new member of the Dbl family. EhGEF2 is the second GEF studied in parasites and in the protozoan Entamoeba histolytica, and it is also the first member of the Dbl family that was found to have Arm repeats. The catalytic domain (DH) of EhGEF2 has the conserved residues T421, N590 and E591, which are important for the activation of the GTPases. Biochemical studies on EhGEF2 showed that it could activate in vitro the amoebic GTPases EhRacA, EhRacB, EhRacC, EhRacD, EhRacG, EhRacH and EhCdc42, being EhRacG its main target. It was found that the DH domain binds specifically phosphatidic acid (PA); docking and lipid dot blot studies indicated that this binding does not interfere with the contact surface of EhRacG. Functional studies showed that both the Arm repeats and the catalytic domain of EhGEF2 participate in its localization at the amoebic membrane. Expression of a negative dominant version of EhGEF2 protein in E. histolytica provoked a 30% decrease in its ability to phagocyte human erythrocytes as well as severe effects on both the proliferation and the cellular chemotaxis which suggest that EhGEF2 participates in these cellular processes.

EhPAK2, a novel p21-activated kinase, is required for collagen invasion and capping in Entamoeba histolytica.

p21-activated kinases (PAKs) are a highly conserved family of enzymes that are activated by Rho GTPases. All PAKs contain an N-terminal Cdc42/Rac interacting binding (CRIB) domain, which confers binding to these GTPases, and a C-terminal kinase domain. In addition, some PAKs such as Cla4p, Skm1p and Pak2p contain an N-terminal pleckstrin homology (PH) domain and form a distinct group of PAK proteins involved in cell morphology, cell-cycle and gene transcription. Here, we describe a novel p21-activated kinase, denominated EhPAK2, on the parasitic protozoan Entamoeba histolytica. This is the first reported Entamoeba PAK member that contains a N-terminal PH domain and a highly conserved CRIB domain. EhPAK2 CRIB domain shares 29% of amino acid identity and 53% of amino acid homology with these of DdPAKC from Dictyostelium discoideum and Cla4p from Saccharomyces cerevisiae and binds in vitro and in vivo to EhRacA GTPase. This domain also possesses the conserved residues His123, Phe134 and Trp141, which are important for the interaction with the effector loop and strand beta2 of the GTPase; and the residues Met121 and Phe145, which are specific for the interaction of EhPAK2 with EhRacA. Functional studies of EhPAK2 showed that its C-terminal kinase domain had activity toward myelin basic protein. Cellular studies showed that Entamoeba trophozoites transfected with the vector pExEhNeo/kinase-myc, had a 90% decrease in the ability to invade a collagen matrix as well as severe defects in capping, suggesting the involvement of EhPAK2 in these cellular processes.

The ABP-120 C-end region from Entamoeba histolytica interacts with sulfatide, a new lipid target.

EhABP-120 is the first filamin identified in the parasitic protozoan Entamoeba histolytica. Filamins are a family of cross-linking actin-binding proteins that promote a dynamic orthogonal web. They have been reported to interact directly with more than 30 cellular proteins and some phosphoinositides. The biochemical consequences of these interactions may have either positive or negative effects on the cross-linking function and also form a link between the cytoskeleton and plasma membrane. In this study, the EhABP-120 carboxy-terminal domain (END) was biochemically characterized. This domain was able to associate to 3-sulfate galactosyl ceramide, a new lipid target for a member of the filamin family. Also, the END domain was able to dimerize "in vitro." Molecular modeling analysis showed that the dimeric region is stabilized by a disulfide bond. Electrostatic and docking studies suggest that an electropositive concave pocket at the dimeric END domain interacts simultaneously with several sulfogalactose moieties of the sulfatide.

L10 ribosomal protein from Entamoeba histolytica share structural and functional homologies with QM/Jif-1: proteins with extraribosomal functions.

In the present work, the complete amino acid sequence of the Entamoeba histolytica ribosomal protein L10 (EhL10) is reported. cDNA of 630bp revealed an open reading frame that encodes a protein of 210 amino acids. Analysis of EhL10 ribosomal protein revealed 75% similarity and 57% identity with QM protein from Homo sapiens and 78 and 60%, respectively, with Arabidopsis thaliana. Western blot analysis of ribosomal proteins from E. histolytica showed that EhL10 protein is part of the ribosomal complex. Immunofluorescence analysis of EhL10 distribution in a transfected E. histolytica strain showed that EhL10 protein was mainly localized in the nucleus of trophozoites. Overexpression of EhL10 ribosomal protein in trophozoites transfected with the pExEhNeo/EhL10 vector exhibited a 60% reduction in cellular growth. DNA mobility-shift assays demonstrated that EhL10 ribosomal protein was able to destabilize the activating protein 1 (AP-1) complex binding specifically to the c-Jun-like protein. It is proposed in this study that the complex formation of EhL10 with c-Jun-like protein interferes with transcriptional activation of genes controlled by Jun (i.e. gene involved in cell growth). It is also being reported identification of a member of the AP-1 complex, the c-Jun-like protein, in nuclear extracts of E. histolytica using human-specific antibodies against this protein. The observations suggest that EhL10 may have an extraribosomal function in E. histolytica involved in suppression of cell proliferation in E. histolytica similar to the QM protein.