Mathisson-Papapetrou-Tulczyjew-Dixon (MPTD) equations in the Lagrangian formulation correspond to the minimal interaction of spin with gravity. Due to the interaction, in the Lagrangian equations instead of the original metric g emerges spin-dependent effective metric G = g + h(S). So we need to decide, which of them the MPTD particle sees as the space-time metric. We show that MPTD equations, if considered with respect to original metric, have unsatisfactory behavior: the acceleration in the direction of velocity grows up to infinity in the ultra-relativistic limit. If considered with respect to G, the theory has no this problem. But the metric now depends on spin, so there is no unique space-time manifold for the Universe of spinning particles: each particle probes his own three-dimensional geometry. This can be improved by adding a non-minimal interaction of spin with gravity through gravimagnetic moment. The modified MPTD equations with unit gravimagnetic moment have reasonable behavior within the original metric.Equations of motion of a rotating body in a curved background are formulated usually in the multipole approach to describe the body [1][2][3][4][5][6][7][8]. We consider the Mathisson-Papapetrou-Tulczyjew-Dixon (MPTD) equations, which describe the body in the pole-dipole approximation, in the form studied by Dixon (for the relation of the Dixon equations with those of Papapetrou and Tulczyjew see p. 335 in [4] as well as the recent works [7,8]):(our S µν is twice that of Dixon). They are widely used now in computations of spin effects in compact binaries and rotating black holes [9][10][11][12][13][14][15][16], so our results may be relevant in this framework. In the multipole approach, x µ (τ ) is called the representative point (centroid) of the body, the antisymmetric spin-tensor S µν (τ ) is associated with the inner angular momentum and the vector P µ (τ ) is called momentum.A few words about our notation. As we will discuss the ultra-relativistic limit, we do not assume the proper-time parametrization, that means that we do not add the equation g µνẋ µẋν = −c 2 to the system (1). Our variables are taken in an arbitrary parametrization τ , andẋ µ = , and so on. The notation for the scalar functions constructed from second-rank tensors are θS = θ µν S µν , S 2 = S µν S µν . In the present work we continue the analysis of the MPTD equations on the base of Lagrangian formulation developed in the recent work [17], and discuss the necessity of generalizing the formalism by including an interaction of the spin with gravity through non vanishing gravimagnetic moment. We discuss the behavior of the MPTD-particle in ultra-relativistic limit, when the speed of the particle approximates the speed of light. Since we are interested in the influence of the spin on the particle's trajectory, we eliminate the momenta from the MPTD equations, thus obtaining a second-order equation for the representative point x µ (τ ). To achieve this, we compute the derivative of the spin supplementary condition (SSC), ∇(S µν ...