  We derive the circular velocity curves of the gaseous and stellar discs of
UGC 4056, a giant barred galaxy with an active galactic nucleus (AGN). We
analyse UGC 4056 using the 2D spectroscopy obtained within the framework of the
Mapping Nearby Galaxies at APO (MaNGA) survey. Using images and the colour
index g-r from the Sloan Digital Sky Survey (SDSS), we determined the tilt of
the galaxy, which allows us to conclude that the galaxy rotates clockwise with
trailing spiral arms. We found that the gas motion at the central part of the
UGC 4056 shows peculiar features. The rotation velocity of the gaseous disc
shows a bump within around three kiloparsecs while the rotation velocity of the
stellar disc falls smoothly to zero with decreasing galactocentric distance. We
demonstrate that the peculiar radial velocities in the central part of the
galaxy may be caused by the inflow of the gas towards the nucleus of the
galaxy. The unusual motion of the gas takes place at the region with the
AGN-like radiation and can be explained by the gas response to the bar
potential.
