Pyk2 phosphorylates the E2. (A) HEK293TT cells were transfected with GFP-Pyk2 WT or GFP-Pyk2 KD and FLAG-HPV-31 or FLAG-HPV-16 E2. FLAG-HPV-E2 was immunoprecipitated with M2 (FLAG) antibodies, and complexes were blotted with pTyr-1000, M2 (FLAG), and Pyk2 antibodies. (B) HEK293TT cells were transfected with FLAG-Pyk2 WT or FLAG-Pyk2 KD and FLAG-HPV-31 E2 fragments (aa 1 to 106, 176 to 372, 107 to 372, and 205 to 372). FLAG-HPV-31 E2 and FLAG-Pyk2 were immunoprecipitated with M2 (FLAG) antibodies, and complexes were blotted with pTyr-1000 and M2 (FLAG) antibodies. Phospho-E2 fragments are identified by an asterisk (*).