Interactions of ADAM15 splice variants with SH3 domain proteins

• Main Author: Shedden, Elizabeth
• Published: University of East Anglia 2015
• Subjects: 540
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.656136

A Disintegrin And Metalloproteinase 15 (ADAM15) is a membrane-bound metalloproteinase which has been shown to be significantly raised throughout breast cancer progression. The intracellular domain (ICD) of ADAM15 exists in multiple splice variants that contain varied combinations of polyproline regions, which interact preferentially with proteins containing Src Homology 3 (SH3) domains. Patients suffering from node-negative breast cancer exhibited a poorer prognosis when expressing high levels of variant A and B whereas those patients suffering from node-positive cancer exhibited an improved prognosis when expressing high levels of ADAM15 variant C. Nuclear Magnetic Resonance (NMR) spectroscopy titrations were used to elucidate the interaction interface between the ADAM15 ICD variants and the SH3 domains of Grb2, Src and Brk. Chemical Shift Perturbations (CSPs) indicated that Grb2 interacted with all ADAM15 ICD variants via residues 22Glu, 44Trp and 56Phe. Analysis of the common regions of the ICD variants implicated the polyproline region 4 in this interaction. The Src SH3 domain interacted with ADAM15 B, C and E via residues 17Arg, 21Asp, 40Trp and 56Ser-58Tyr; residues which are present in the hydrophobic pocket of the domain. This interaction likely involves a RPLPXDPV motif apparent in polyproline regions 2 and 3 of the ADAM15 ICD. The Brk SH3 domain also interacted with ADAM15 B via residues 34Arg, 56Trp, 74Val, 77Asn and 79Leu in a manner similar to the internal interaction of the Brk SH3 domain with its own linker region. ADAM15 D does not interact with any of the SH3 domains as it does not include any polyproline regions. This work has highlighted the manner by which certain SH3 domains preferentially interact with the polyproline regions of the ADAM15 ICD and open a line of investigation into the downstream functions of these interactions particularly with regards to breast cancer expression.