Appears to initiate or participate in signaling events that regulate the actin recruitment, which ultimately leads to internalization. Secreted via type III secretion system and translocated into host cell. Phosphorylated on a tyrosine on attachment to the host cell. Tyrosine phosphorylation is temporally and spatially associated with recruitment of actin to the site of chlamydial entry. Phosphorylated Tarp seems to remain cytoplasmically exposed on the inclusion membrane at one side of internalized elementary bodies for several hours after entry. Transcribed from mid to late cycle in the chlamydial developmental cycle. Belongs to the chlamydial CPn_0572/CT_456/TC_0741 family.