KChannelDB: Extraction of mutation data from the literature

2005, KChannelDB.

This data was extracted from Medline abstracts and full texts (when available) in an automated manner.

The table below describes the selected point mutation and provides links to other documents. The sentence(s) where the point mutation R171V was found are listed after the table.

The mutated residues are also indicated in the family sequence alignments and hyperlinked to the corresponding mutation pages.

Point mutation R171V in KAT1_ARATH

Point mutation:	R171V
Cited point mutation:	Arg171Val,Arg171
Domain:	TRANSMEM IV
General numbering (KChannelDB):	450
Protein:	KAT1_ARATH (KAT1,At5g46240,MPL12.)	Swiss-Prot Cross-reference table Family page
Other point mutations / same protein / same position	Point mutations at position 171 in KAT1_ARATH
Other point mutations / same protein	List of mutations in KAT1_ARATH
Family alignments	AKT-like Inward rectifiers 6TMs Plant potassium channels
Other point mutations / same position	Position 173 in AKT-like Inward rectifiers 6TMs family Position 173 in Plant potassium channels family
Reference:	Molecular dissection of the contribution of negatively and positively charged residues in S2, S3, and S4 to the final membrane topology of the voltage sensor in the K+ channel, KAT1. Sato Y, Sakaguchi M, Goshima S, Nakamura T, Uozumi N J Biol Chem 2003 Apr 11;278(15):13227-34. Epub 2003 Jan 29.	Medline
Other point mutations / same article	List
Text source	HTML full text
Validation status	Not yet checked

Relevant sentences:

R171V

In contrast , the R165V and R171V mutants had no K + channel activity , showing that these two residues play an important role in the gating charge movement , which is coupled to the opening and closing of the pore
B , membrane topology of the R165V , R171V , R174V , R176V , or R177V mutants
K + current was detected (+) in the R174V- , R176V- , or R177V-expressing oocytes but not detected (ND) in the D95V- , D105V- , D141V- , R165V- or R171V-expressing oocytes

Arg171

Interactions between Asp105 and Arg171 and between negative residues in S2 or S3 and Arg174 may be formed transiently during membrane integration
To produce PL fusion proteins , DNA encoding Met1-Arg165 , Met1-Arg171 , Met1-Trp173 , Met1-Arg174 , Met1-Arg176 , Met1-Arg177 , or Met1-Arg184 from KAT1 was fused to DNA coding for PL gly using a two-step PCR approach (18 )
Arg171 in S4 Is Involved in Stabilization of S4 Topology-- The interaction between negatively charged residues in S2 and S3 and positively charged residues in S4 is important in the voltage sensor operation (1 , 3-5 , 7 )
A series of S1-4-PL / PLgly fusion proteins in which Arg165 , Arg171 , Arg174 , Arg176 , or Arg177 in S4 was replaced by valine was constructed to eliminate single positive charges (Fig. 4 , A and B)
Interaction between Asp105 and Arg171 occurs during membrane integration of S3-S4
This suggests that the Asp105-Arg171 interaction is involved in supporting the membrane spanning of S4 during membrane integration
The N-terminal Region of S4 up to Arg174 Is Required for S4 Membrane Spanning-- Although the Asp105-Arg171 interaction is important in S4 membrane spanning , other forces and components must also be involved
S1-Arg171-PLgly and S1-Trp173-PLgly each gave two glycosylated bands (Fig. 5 B , lanes 4 and 6) , whereas S1-Arg174-PLgly gave only the mono-glycosylated band (lane 8) , suggesting that Arg174 is involved in retaining S4 in the membrane
The presence of Arg171 resulted in both mono- and di-glycosylated forms , and the intensity of the mono-glycosylated form increased with the Trp173-containing construct , an effect not seen using the Asp141 form (Fig. 5 B)
Compared with the original S1-Arg174-PLgly and S1-Arg177-PLgly , those proteins containing D95V or D95V and D105V showed a weaker glycosylated band (Fig. 6 , B and D , lanes 2 , 4 , and 6) , whereas those containing only D105V showed two glycosylated bands (lane 8) , confirming the association between Asp105 and Arg171 seen in Fig. 4 D
Single mutation of the negatively charged residues , Asp95 , Asp105 , and Asp141 , had a clear effect on KAT1 topology , whereas single mutation of the positively charged residues , Arg165 , Arg171 , Arg174 , Arg176 , and Arg177 , did not
3 and 6 ) , and in the case of the D105R mutant , this effect was overcome by additional mutation of Arg171 in S4 to aspartate (Fig. 4 D) , showing that pairing of Asp105 and Arg171 occurs during the step of membrane integration of S3 and S4
The membrane integration of S3-S4 in KAT1 is assisted by interactions among Asp141 and positive S4 residues , Asp105 and Arg171 , and negative S2 residues and Arg174
Since these residues reside within the membrane and Asp105 is located on the cytosolic side of the membrane according to a map of charged residues in the animal Shaker channel (2-6 ) , Asp105 and Arg171 may not be in close proximity to one another in the final configuration of KAT1 in the membrane
In the Drosophila Shaker K+ channel , residues Glu283 , Arg368 , and Arg371 (corresponding to Asp95 , Arg171 , and Arg174 in KAT1 ; Fig. 1 B) form one charge network , whereas residues Glu293 , Asp316 , and Lys374 (corresponding to Asp105 , Asp141 , and Arg177 in KAT1) form the other (10 )
If the same applies to KAT1 , Asp105 and Arg171 would belong to different networks (pairing groups) in the final topology , and the Asp105-Arg171 interaction , which was shown to affect the retention of S4 in the membrane (Fig. 4 D) , may represent a transient initial step in the insertion process
We estimate that , during membrane integration , the interaction between Arg171 and Asp105 is stronger than that between Arg174 and as yet undefined negative residues since the former interaction could be detected by the double mutation approach (Fig. 4 D)

F.Horn (kchanneldbcmbi.ru.nl), 17-Aug-2005