Bacillus subtilis is a Gram-positive model organism found worldwide in environments with different nutrients and trace elements. To adapt to these changing growth conditions, B. subtilis has a high capacity for protein secretion and employs various systems to maintain the intracellular metal levels. Manganese is an important transition metal and functions as the cofactor in different metalloenzymes. Cytosolic Mn-requiring enzymes can acquire metals from buffered intracellular pools, but the mechanisms of metalation of exported enzymes are unclear. Here, we show that widely conserved TerC family proteins function in metalation of exoenzymes during or after their secretion process through the general secretion (Sec-dependent) pathway. B. subtilis cells lacking MeeF and MeeY have a reduced capacity for protein secretion and a dramatically reduced level of manganese in the secreted proteome. In the absence of TerC proteins, misfolded or unfolded proteins may stall the secretion translocon (SecYEG). The membrane protease FtsH, which can degrade dysfunctional SecY, is essential for cell viability. MeeF and MeeY can also influence the efficient function of Mn-dependent lipoteichoic acid synthase LtaS by metalation of Mn into its extracytoplasmic active site. Overall, MeeF and MeeY have functions in the co-translocational metalation of Mn-requiring membrane and extracellular enzymes (Chapter 2). The jamming of translocon caused by a lack of TerC proteins MeeF and MeeY may influence other cellular processes in B. subtilis. We provide evidence that MeeF and MeeY are involved in the swarming, sporulation, and natural competence. The double mutant meeFmeeY has defective swarming motility and decreased flagella production. Besides, cells lacking MeeF and MeeY in CU1065 strain background show defects in sporulation and a lower transformation efficiency. These defects indicate that clients other than LtaS require TerC proteins for metalation, and the impaired secretion in the cells without TerC proteins can cause pleiotropic phenotypes in B. subtilis (Chapter 3). Finally, we discuss the strategies employed by bacterial cells to metalate membrane-bound and secreted metalloenzymes which are involved in cell envelope homeostasis (Chapter 4).