A photon is a quantum mechanical entity/particle in the table of elementary particles in the standard model of particle physics.. In the quantum field theory model we have of particles and interactions, the particles interact with the exchange of particles, and in order for the photon to lose energy it has to interact with something.
At present, quantization of gravity is only effective, not definitively modeled.There is no standard model for gravitational field and photon interactions. In what follows I am giving an answer to your questions ,if the final theory of quantized gravity can be seen to lead to diagrams analogous to the diagrams of the other three forces. At the moment an effective gravitational quantum theory is used for cosmological problems, analogous to the one for the other forces.
In this effective gravity, one can have Feynman diagrams of the photon interacting with a gravitational field represented by the graviton, your "other boson". In this publication, there are diagrams for effective photon interactions with gravitons.
FIG. 1: Feynman diagrams for the photon-graviton scattering, dashed lines represent gravitons, wavy lines represent photons.
Diagrams (a) and (b) give the amplitude M1, Eq. (24); diagram (c) gives the amplitude M2, Eq. (25); diagram (d) gives the
amplitude M3, Eq. (26).
Taking the simplest diagram (a) the energy lost (or gained: blue shift) from the photon in a strong gravitational field will be given to the field (or taken from), i.e. the mass source of that field.
The subject of quantization of gravity is a current research question. The red shift and blue shift are not treated at the quantum level, where the photon belongs, but at the classical general relativity and electromagnetic level. We have to wait for the theory of quantized gravity to have the correct modeling.
