Very-long-baseline interferometry (VLBI) observations enable us to study the parsec-scale structure of active galactic nuclei (AGN), and connect changes in the jet brightness distribution, morphology, and opacity to the multiwavelength variability exhibited by these sources. In this talk, I will discuss the connection between the radio and gamma-ray variability in the high-redshift blazar, TXS 1508+572 (z=4.31). The source exhibited a bright gamma-ray flare in February 2022, after which we initiated a multiwavelength follow-up campaign, including three epochs of multi-frequency VLBI observations. This is the first case of such a multiwavelength campaign, including VLBI, on a gamma-flaring AGN at z>4. Our data provided a comprehensive insight into the nature of the flare, and the VLBI observations revealed possible sites for the gamma-ray production. We found that the jet component was not ejected during the 2022 flare, and we conclude that an interaction between a standing and a traveling shock can be the reason for the gamma-ray flare. The spectral energy distribution constructed from the multiwavelength data can be described with a single-zone leptonic model, and the fit parameters are in good agreement with the ones derived from the radio data.