title: Synaptotagmin I delays the fast inactivation of Kv1.4 channel through interaction with its N-terminus.
abstract: BACKGROUND
  The voltage-gated potassium channel Kv1.4 is an important A-type potassium channel and modulates the excitability of neurons in central nervous system. Analysis of the interaction between Kv1.4 and its interacting proteins is helpful to elucidate the function and mechanism of the channel.
  
  
  RESULTS
  In the present research, synaptotagmin I was for the first time demonstrated to be an interacting protein of Kv1.4 and its interaction with Kv1.4 channel did not require the mediation of other synaptic proteins. Using patch-clamp technique, synaptotagmin I was found to delay the inactivation of Kv1.4 in HEK293T cells in a Ca2+-dependent manner, and this interaction was proven to have specificity. Mutagenesis experiments indicated that synaptotagmin I interacted with the N-terminus of Kv1.4 and thus delayed its N-type fast inactivation.
  
  
  CONCLUSIONS
  These data suggest that synaptotagmin I is an interacting protein of Kv1.4 channel and, as a negative modulator, may play an important role in regulating neuronal excitability and synaptic efficacy.
authors.forename: Chunliang
authors.initials: C
authors.lastname: Xie
authors.forename: Haibo
authors.initials: H
authors.lastname: Su
authors.forename: Tianyao
authors.initials: T
authors.lastname: Guo
authors.forename: Yizhong
authors.initials: Y
authors.lastname: Yan
authors.forename: Xiaozhen
authors.initials: X
authors.lastname: Peng
authors.forename: Rui
authors.initials: R
authors.lastname: Cao
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Chen
authors.affiliation: Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, P, R, China. wang_xianchun@263.net.
authors.forename: Xianchun
authors.initials: X
authors.lastname: Wang
authors.forename: Songping
authors.initials: S
authors.lastname: Liang
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002846:Chromatography, Affinity; D057809:HEK293 Cells; D006624:Hippocampus / Q000378:metabolism; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D015640:Ion Channel Gating; D007700:Kinetics; D051665:Kv1.4 Potassium Channel / Q000737:chemistry* / Q000378:metabolism*; D050505:Mutant Proteins / Q000378:metabolism; D011485:Protein Binding; D040901:Proteomics; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D013329:Structure-Activity Relationship; D050863:Synaptotagmin I / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
chemical_list: D051665:Kv1.4 Potassium Channel; D050505:Mutant Proteins; D050863:Synaptotagmin I; D002118:Calcium