The Protein Encoded byNCgl1221inCorynebacterium glutamicumFunctions as a Mechanosensitive Channel

Abstract

The function of the NCgl1221-encoded protein of Corynebacterium glutamicum was analyzed using Bacillus subtilis as host because a method for preparing the giant provacuole required for electrophysiological studies has been established. Expression of NCgl1221 in a strain deficient in mscL and ykuT, both of which encode mechanosensitive channels, resulted in an 8.9-fold higher cell survival rate upon osmotic downshock than the control. Electrophysiological investigation showed that the giant provacuole prepared from this strain, expressing NCgl1221, exhibited significantly higher pressuredependent conductance than the control. These findings show that the NCgl1221-encoded protein functions as a mechanosensitive channel.

L-Glutamate Secretion by the N-Terminal Domain of theCorynebacterium glutamicumNCgl1221 Mechanosensitive Channel

“…Electrophysiological analyses have indicated that NCgl1221 functions as a mechanosensitive channel. 19,20) Moreover, it was found that L-glutamate is indeed transported through this channel. 31) In the present study, we constructed a series of C-terminally truncated mutants of NCgl1221 to investigate the role of this C-terminal domain in glutamate secretion.…”

“…19) The mechanosensitive channel activity of NCgl1221 was also confirmed by patch-clump analysis using giant provacuoles of B. subtilis lacking mechanosensitive channels, MscL and YkuT (an MscS homolog). 20) These results suggest that NCgl1221 encodes a long-elusive L-glutamic acid exporter. Very recently, it was found that the NCgl1221 channel serves as a path for glutamate efflux.…”

“…17,18) Patch-clamp analyses by independent research groups have confirmed this model. 19,20) Mechanosensitive channels are gated by the sensing of changes in membrane tension to protect cells from bursting upon hypoosmotic shock. [21][22][23][24][25] E. coli is known to have two major mechanosensitive channels, MscL y To whom correspondence should be addressed.…”

Glutamate Dehydrogenases: Enzymology, Physiological Role and Biotechnological Relevance

“…In addition, this is the first response of C. glutamicum to membrane tension alterations, which triggers all other metabolic adaptations leading to efficient glutamate production. The NCgl1221 (yggB) product has 4 transmembrane segments, is located in the cytoplasmic membrane [117] and has been recently shown to work as a mechanosensitive channel able to increase the cell survival rate of Bacillus subtilis after osmotic down-shock [118].…”

A role of the transcriptional regulator LldR (NCgl2814) in glutamate metabolism under biotin-limited conditions in Corynebacterium glutamicum

“…59 SUPKULSUTRA et al surfactants or penicillin treatments (Nara et al, 1964;Takinami et al, 1965). It was recently shown that the NCgl1221 gene encoding a mechanosensitive channel is involved in the mechanism of L-glutamate secretion (Borngen et al, 2010;Hashimoto et al, 2010;Nakamura et al, 2007;Wachi, 2013). Specific mutations of NCgl1221 protein led to a constitutive L-glutamate secretion without any inducing treatments, while disruption of NCgl1221 greatly diminished L-glutamic acid secretion (Nakamura et al, 2007;Nakayama et al, 2012).…”