A C2 domain is a protein structural domain involved in targeting proteins to cell membranes. The typical version (PKC-C2) has a beta-sandwich composed of 8 beta-strands that co-ordinates two or three calcium ions, which bind in a cavity formed by the first and final loops of the domain, on the membrane binding face. The C2 domain of PRKCQ, the closest relative of PRKCQ in the PKC family, was found to be a novel Tyr(P)-binding domain, which could specifically bind a Tyr(P)-containing peptide derived from CDCP1, a protein known to be phosphorylated on tyrosine by activated Src kinase (1).

Reference
1. Stahelin, R.V. (2012) PRKCQ C2 domain is a phosphotyrosine binding module that plays a key role in its activation . J Biol Chem, 287, 30518-28. PMID: 22787157

    Cbl-PTB is composed of three interacting domains: a four-helix bundle (4H), an EF-hand calcium-binding domain, and a divergent SH2 domain. The calcium-bound EF-hand wedges between the 4H and SH2 domains, and roughly determines their relative orientation. The three domains together form an integrated phosphoprotein-recognition module (1).

Reference
1. https://prosite.expasy.org/rule/PRU00839

    The E3 ubiquitin ligase Hakai targets tyrosine-phosphorylated E-cadherin via an uncharacterized domain. In recent study, the crystal structure of Hakai (amino acids 106–206) revealed that it forms an atypical, zinc-coordinated homodimer by utilizing residues from the phosphotyrosine-binding domain of two Hakai monomers. Hakai dimerization allows the formation of a phosphotyrosine-binding pocket that recognizes specific phosphorylated tyrosines and flanking acidic amino acids of Src substrates, such as E-cadherin, cortactin and DOK1. NMR and mutational analysis identified the Hakai residues required for target binding within the binding pocket, now named the HYB domain. The HYB domain is structurally different from other phosphotyrosine-binding domains and is a potential drug target due to its novel structural features (1).

Reference
1. Mukherjee, M. (2012) Structure of a novel phosphotyrosine-binding domain in Hakai that targets E-cadherin. EMBO J, 31, 1308-19. PMID: 22252131

    RKIP contains a novel phospho-amino acid binding domain. Substitutions in the ligand binding site of RKIP compromise the stability of the phosphorylated Raf-RKIP complex. Notably, PKM2 binds directly and selectively to tyrosine (Tyr, Y)-phosphorylated peptides, and expression of the phosphotyrosine-binding form of PKM2 is required for the rapid growth of cancer cells (1).
1. Kaneko T, Joshi R, Li SS. (2012) Phosphotyrosine recognition domains: the typical, the atypical and the versatile. Cell Commun Signal, 10(1), 32. PMID: 23134684

    Pleckstrin homology domain (PH domain) is a protein domain of approximately 120 amino acids that occurs in a wide range of proteins involved in intracellular signaling or as constituents of the cytoskeleton. This domain can bind phosphatidylinositol lipids within biological membranes, and proteins such as the βγ-subunits of heterotrimeric G proteins. In addition, recent study showed that GEP100, through its pleckstrin homology domain, bound directly to Tyr1068/1086-phosphorylated EGFR to activate Arf6 (1).

Reference
1. Morishige, M. (2008) GEP100 links epidermal growth factor receptor signalling to Arf6 activation to induce breast cancer invasion. Nat Cell Biol, 10, 85-92. PMID: 18084281

    The phosphotyrosine-binding (PTB) or phosphotyrosine interaction domain (PID) was originally identified in the protein, Shc, as a domain that could bind tyrosine-phosphorylated growth factor receptors. It was the second domain found to bind phosphotyrosine-containing peptides, having been preceded by the discovery of the Src homology 2 (SH2) domain several years earlier. Proteins with this domain are involved in diverse cellular functions, ranging from receptor signaling to protein targeting (1).

Reference
1. Zeng, L. (2014) Structural insights into FRS2 PTB domain recognition by neurotrophin receptor TrkB. Proteins, 82, 1534-41. PMID: 24470253

    The SH2 (Src Homology 2) domain is a structurally conserved protein domain contained within the Src and in many other intracellular signal-transducing proteins. SH2 domains allow proteins containing those domains to dock to phosphorylated tyrosine residues on other proteins. SH2 domains are commonly found in adapter proteins that aid in the signal transduction of receptor tyrosine kinase pathways. The yeast genome encodes only one SH2 domain-containing protein, the transcription factor Spt6. Recent study demonstrated that the Spt6 SH2 domain region can binds to Ser-phosphorylated CTD (1).

Reference
1. Kaneko, T. (2012) Phosphotyrosine recognition domains: the typical, the atypical and the versatile. Cell Commun Signal, 10, 32. PMID: 23134684