Protein proximity assay in formalin fixed paraffin embedded tissue using caged haptens

A compound having Formula (IE) or (IF):

• wherein
• “Hapten” is selected from the group consisting of nitropyrazole, nitrophenyl, benzofuran, dinitrophenol, biotin, digoxigenin, fluorescein, an oxazole, an oxazole sulfonamide, a thiazole, hydroxyquinoxaline, or a thiazole sulfonamide;
• Y is selected from a carbonyl-reactive group, an amine-reactive group, or a thiol-reactive group;
• A is a group comprising a branched or unbranched, substituted or unsubstituted, saturated or unsaturated aliphatic group having between 1 and 15 carbon atoms, and optionally having one or more heteroatoms selected from the group consisting of O, N, or S, wherein A includes a group having Formula (IIID):
• wherein d and e are integers each independently ranging from 1 to 12;
• Q is a bond, O, or N(Rc)(Rd);
• Ra and Rb are independently H, a C1-C4 alkyl group, Rc and Rd are independently CH3 or H;
• X is a bond, or a group comprising a branched or unbranched, substituted or unsubstituted, saturated or unsaturated aliphatic group having between 1 and 30 carbon atoms, and optionally having one or more heteroatoms selected from the group consisting of O, N, or S, and wherein X includes a group having Formula (IIIA):
• wherein d and e are integers each independently ranging from 4 to 18;
• Q is a bond, O, S, or N(Rc)(Rd);
• Ra and Rb are independently H, a C1-C4 alkyl group, F, Cl, or N(Rc)(Rd);
• and Rc and Rd are independently CH3 or H;
• W is a 5-, 6-, or 7-membered substituted or unsubstituted aromatic or heterocyclic group;
• each R1 is independently selected from H, F, Cl, Br, I, —O-methyl, —O-ethyl, —O-n-propyl, —O-iso-propyl;
• —O-n-butyl, —O-sec-butyl, or —O-iso-butyl;
• a —S-alkyl group having between 1 and 4 carbon atoms;
• an —O-alkyl group having between 1 and 4 carbon atoms;
• a —N(H)-alkyl group having between 1 and 4 carbon atoms;
• a —N-(alkyl)2 group having between 1 and 6 carbon atoms;
• an alkyl group having between 1 and 4 carbon atoms and optionally substituted with N or S;
• cyano groups;
• and carboxyl groups;
• V is a substituted or unsubstituted alkyl group having between 1 and 4 carbon atoms, or a substituted or unsubstituted —O-alkyl group;
• R3 comprises an enzyme substrate;
• q is 0 or 1;
• s is 0 or an integer ranging from 1 to 4;
• and
• t is 0 or 1.