c-Src activation linked to membrane anchoring: The N-terminal myristoyl group of the SH4 domain of c-Src binds to the SH3 domain outside the membrane. In the presence of lipids, the myristoyl group is released from the SH3 domain and inserts into the lipid membrane, but the fuzzy complex with the SH4 and Unique domains is retained in the membrane-bound form.
Le Roux AL, Mohammad IL, Mateos B, Arbesu M, Gairi M, Khan FA, Teixeira JMC, Pons M.
iScience2019 Feb; 12: 194.
The c-Src oncogene is anchored to the cytoplasmic membrane through its N-terminal myristoylated SH4 domain. This domain is part of an intramolecular fuzzy complex with the SH3 and Unique domains. Here we show that the N-terminal myristoyl group binds to the SH3 domain in the proximity of the RT loop, when Src is not anchored to a lipid membrane. Residues in the so-called Unique Lipid Binding Region modulate this interaction. In the presence of lipids, the myristoyl group is released from the SH3 domain and inserts into the lipid membrane. The fuzzy complex with the SH4 and Unique domains is retained in the membrane-bound form, placing the SH3 domain close to the membrane surface and restricting its orientation. The apparent affinity of myristoylated proteins containing the SH4, Unique, and SH3 domains is modulated by these intramolecular interactions, suggesting a mechanism linking c-Src activation and membrane anchoring.