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005			20250625162502.0
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090			_aB-21163
245	1	0	_aArabidopsis COPT1 copper transporter uses a single histidine to regulate transport activity and protein stability
490	0		_vInternational Journal of Biological Macromolecules, 241, p.124404, 2023
520	3		_aCopper acquisition and subsequent delivery to target proteins are essential for many biological processes. However, the cellular levels of this trace element must be controlled because of its potential toxicity. The COPT1 protein rich in potential metal-binding amino acids functions in high affinity copper uptake at the plasma membrane of Arabidopsis cells. The functional role of these putative metal-binding residues is largely unknown. Through truncations and site-directed mutagenesis, we identified His43, a single residue within the extracellular N-terminal domain as absolutely critical for copper uptake of COPT1. Substitution of this residue with leucine, methionine or cysteine almost inactivated transport function of COPT1, implying that His43 fails to serves as a copper ligand in the regulation of COPT1 activity. Deletion of all extracellular N-terminal metal-binding residues completely blocked copper-stimulated degradation but did not alter the subcellular distribution and multimerization of COPT1. Although mutation of His43 to alanine and serine retained the transporter activity in yeast cells, the mutant protein was unstable and degraded in the proteasome in Arabidopsis cells. Our results demonstrate a pivotal role for the extracellular residue His43 in high affinity copper transport activity, and suggest common molecular mechanisms for regulating both metal transport and protein stability of COPT1.
650	1	4	_aCOPPER TRANSPORTER
650	1	4	_aHISTIDINE
650	1	4	_aARABIDOPSIS
650	1	4	_aPROTEIN STABILITY
650	1	4	_aMETAL LIGAND
700	1	2	_aHe, L.
700	1	2	_aMa, H.
700	1	2	_aSong, W.
700	1	2	_aZhou, Z.
700	1	2	_aMa, C.
700	1	2	_aZhang, H.
856	4	0	_uhttps://drive.google.com/open?id=16FMrcK5rj6A32EHsKAnpf02gesw9f2We&usp=drive_copy _zPara ver el documento ingresa a Google con tu cuenta: @cicy.edu.mx
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