Transmembrane Interactions in the Activation of the Neu Receptor Tyrosine Kinase

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• 作者：Steven O. Smith ; Charles Smith ; Srinivasan Shekar ; Olve Peersen ; Martine Ziliox ; and Saburo Aimoto
• 刊名：Biochemistry
• 出版年：2002
• 出版时间：July 30, 2002
• 年：2002
• 卷：41
• 期：30
• 页码：9321 - 9332
• 全文大小：208K
• 年卷期：v.41,no.30(July 30, 2002)
• ISSN：1520-4995

文摘

The Neu receptor tyrosine kinase is constitutively activated by a single amino acid change inthe transmembrane domain of the receptor. The mutation of Val664 to glutamate or glutamine inducesreceptor dimerization and autophosphorylation of the receptor's intracellular kinase domain. The abilityof this single mutation to activate the receptor is sequence-dependent, suggesting that specific helix-helix interactions stabilize the transmembrane dimer. We have determined the local secondary structureand interhelical contacts in the region of position 664 in peptide models of the activated receptor usingsolid-state rotational resonance and rotational echo double-resonance (REDOR) NMR methods. Intrahelical¹³C rotational resonance distance measurements were made between 1-¹³C-Thr662 and 2-¹³C-Gly665 onpeptides corresponding to the wild-type Neu and activated Neu* transmembrane sequences containingvaline and glutamate at position 664, respectively. We observed similar internuclear distances (4.5 ± 0.2Å) in both Neu and Neu*, indicating that the region near residue 664 is helical and is not influenced bymutation. Interhelical ¹⁵N···¹³C REDOR measurements between Gln664 side chains on opposing heliceswere not consistent with hydrogen bonding between the side chain functional groups. However, interhelicalrotational resonance measurements between 1-¹³C-Glu664 and 2-¹³C-Gly665 and between 1-¹³C-Gly665and 2-¹³C-Gly665 demonstrated close contacts (4.3-4.5 Å) consistent with the packing of Gly665 in theNeu* dimer interface. These measurements provide structural constraints for modeling the transmembranedimer and define the rotational orientation of the transmembrane helices in the activated receptor.