Distinct features of Mycobacterium tuberculosis are a complex cell envelope and that they grow by inserting new cell wall material at their poles, which gives rise to an asymmetric growth pattern and a phenotypically heterogeneous cell population. However, the molecular details of asymmetric polar growth are not completely understood. LamA, a member of the divisome, has been implicated to have a crucial role in asymmetric polar growth. LamA recruits proteins involved in cell wall synthesis, and in this study, Rego and colleagues characterize the role of one of the interacting proteins, polar growth factor A (PgfA), in mycobacterial growth and division. The authors found that in the model organism Mycobacterium smegmatis, PgfA is essential for polar growth and localizes primarily to the old pole. Moreover, PgfA interacts with MmpL3, which is the essential mycolic acid flippase that transports trehalose monomycolate (TMM) across the plasma membrane to the periplasm. Further analysis suggests that PgfA is a periplasmic protein that binds TMM and is part of the TMM transport pathway in the periplasm. In sum, the data suggest that PgfA is an important factor in determining cell wall composition and incorporation at the old pole in mycobacteria.