  We review the General Relativistic model of a (quasi) point-like particle
represented by a massive shell of neutral matter which has vanishing total
energy in the small-volume limit. We then show that, by assuming a Generalised
Uncertainty Principle, which implies the existence of a minimum length of the
order of the Planck scale, the total energy instead remains finite and equal to
the shell's proper mass both for very heavy and very light particles. This
suggests that the quantum structure of space-time might be related to the
classical Equivalence Principle and possible implications for the late stage of
evaporating black holes are briefly mentioned.
