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Las proteínas PE/PPE median el transporte de nutrientes a través de la membrana externa del Mycobacterium

Qinglan Wang¹, Helena I M Boshoff¹, Justin R Harrison²

¹Tuberculosis Research Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.

Science (New York, N.Y.)

|March 7, 2020

Resumen

El crecimiento de la Mycobacterium tuberculosis es inhibido por el 3,3-bis-di-metilsulfonilpropionamida (3bMP1). Las mutaciones en PPE51 y el componente de la pared celular fitocerol cincococerosato afectan el transporte y la replicación de nutrientes.

Área de la Ciencia:

Microbiología
Biología celular
La bioquímica

Sus antecedentes:

Mycobacterium tuberculosis posee una membrana externa única que carece de porinas convencionales para el transporte de solutos.
Las familias de prolina-prolina-glutamato (PPE) y prolina-glutamato (PE) son poco conocidas en la fisiología micobacteriana.

Objetivo del estudio:

Investigar el mecanismo de la inhibición de la 3,3-bis-di ((metilsulfonil) propionamida (3bMP1) de M. tuberculosis.
Identificar el papel de PPE51 y otros miembros de la familia PE/PPE en el transporte de nutrientes y la integridad de las paredes celulares.

Principales métodos:

Cribado genético para los mutantes de M. tuberculosis resistentes al 3bMP1.
Análisis de las deleciones genéticas (PPE51) y su impacto en el crecimiento.
Investigación del papel del cincococerosato de ftiocerol en la permeabilidad de la membrana externa de M. tuberculosis.

Principales resultados:

La resistencia a 3bMP1 está relacionada con mutaciones en PPE51.
La eliminación de PPE51 dificulta el crecimiento de M. tuberculosis en propionamida, glucosa y glicerol.
La pérdida de fitocerol cincococerosato restaura el crecimiento en los mutantes de PPE51.
Otras proteínas PE/PPE están involucradas en el transporte específico del sustrato dependiente del fitocerol cincococerosato.

Conclusiones:

PPE51 y potencialmente otras proteínas PE/PPE funcionan como canales específicos para el soluto en la membrana externa de M. tuberculosis.
El fitocerol cincococerosato es crucial para regular la permeabilidad de la membrana externa, influyendo en la absorción de nutrientes.
Este estudio revela un nuevo mecanismo para el transporte de nutrientes en M. tuberculosis, distinto de los porinos canónicos.

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