LMTK3 and breast cancer: The activity of Rab11-FIP1 has been shown regulated by phosphorylation through 2 different kinases so far: Lemur Tyrosine Kinase 3 (LMTK3) and MAP/Microtubule Affinity-Regulating Kinase 2 (MARK2).The LMTK3 kinase promotes S435 phosphorylation of Rab11-FIP1 in response to HGF stimulation (10) and has been studied for its role in breast cancer (56).The MARK2 kinase was shown to promote phosphorylation of S234 in Rab11-FIP1 and promoted polarization of MDCK cells upon a calcium switch.