Table 2.

Features used in the detection of phosphorylation-interaction relations

Type	Feature	Description
T, C	SSI	Substrate is the same as interactant
T	IMP	One of the interactants is mentioned as being ‘phosphorylated’ (phosphorylated A binds to B)
T	CONJ	P and I are mentioned in a conjunction (there are five types of conjunctions captured in five different features)
C	ACTION	P and I are mentioned in a Subject–Verb–Object relationship (A phosphorylation leads to interaction with B)
T, C	DEPEND	I mentioned to be dependent on P (phosphorylation-dependent interaction of A to B)
T	PFIRST	P mentioned before I in the sentence
T	IFIRST	I mentioned before P in the sentence
T	WLR	There is a word/phrase between P and I hinting to a directionality of events from left to right (leads to)
T	WRL	There is a word/phrase between P and I hinting to a directionality of events from right to left (requires)
C	NEG	One of the events or the action is being negated (phosphorylated A does not bind to B)
C	HEDGE	One of the events or the action is mentioned with hedging (phosphorylated A might bind to B)
T	RELAPPB	P or I is mentioned in a relative clause or appositive referring to a protein (A, which interacts with B, is phosphorylated by C)
T	RELAPPG	I is mentioned in a relative clause or appositive referring to the phosphorylation (phosphorylation of A, which increased the interaction with B)

The type column specifies if the feature is used in the detection of the temporal relation (T), causal relation (C) or both (T, C). The feature column lists the features by name and the description column gives a description of each feature. ‘P’ is short for phosphorylation and ‘I’ is short for interaction.