Electrophysiological characterization of the mechanosensitive channel mscCG in corynebacterium glutamicum

Yoshitaka Nakayama, Kenjiro Yoshimura, Hidetoshi Iida

研究成果: Article査読

26 被引用数 (Scopus)

抄録

Corynebacterium glutamicum MscCG, also referred to as NCgl1221, exports glutamate when biotin is limited in the culture medium. MscCG is a homolog of Escherichia coli MscS, which serves as an osmotic safety valve in E. coli cells. Patch-clamp experiments using heterogeneously expressed MscCG have shown that MscCG is a mechanosensitive channel gated by membrane stretch. Although the association of glutamate secretion with the mechanosensitive gating has been suggested, the electrophysiological characteristics of MscCG have not been well established. In this study, we analyzed the mechanosensitive gating properties of MscCG by expressing it in E. coli spheroplasts. MscCG is permeable to glutamate, but is also permeable to chloride and potassium. The tension at the midpoint of activation is 6.68 ± 0.63 mN/m, which is close to that of MscS. The opening rates at saturating tensions and closing rates at zero tension were at least one order of magnitude slower than those observed for MscS. This slow kinetics produced strong opening-closing hysteresis in response to triangular pressure ramps. Whereas MscS is inactivated under sustained stimulus, MscCG does not undergo inactivation. These results suggest that the mechanosensitive gating properties of MscCG are not suitable for the response to abrupt and harmful changes, such as osmotic downshock, but are tuned to execute slower processes, such as glutamate export.

本文言語English
ページ(範囲)1366-1375
ページ数10
ジャーナルBiophysical Journal
105
6
DOI
出版ステータスPublished - 2013 9月 17
外部発表はい

ASJC Scopus subject areas

  • 生物理学

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