Involved in cell wall biosynthesis. May be responsible for the transfer of arabinogalactan onto peptidoglycan. In vitro, has pyrophosphatase activity. Forms homodimers and homotetramers. Localizes at regions of strong cell wall biosynthesis, such as the poles and the division plane. Both the C-terminal LCP and LytR_C regions are essential for function. The N-terminal region is not strictly required. Essential, it cannot be deleted. Conditional silencing of the gene results in severe growth defects and drastic morphological changes. The lcpA-silencing strain contains significantly less mycolic acids and a reduced amount of arabinogalactan. Belongs to the LytR/CpsA/Psr (LCP) family.