Essential component of the PAM complex, a complex required for the translocation of transit peptide-containing proteins from the inner membrane into the mitochondrial matrix in an ATP-dependent manner. Seems to control the nucleotide-dependent binding of SSC1 to substrate proteins (By similarity). Component of the PAM complex, at least composed of mtHsp70, MGE1, TIM44, PAM16, PAM17 and PAM18. Belongs to the GrpE family.