PKC isoforms activate LRRK1 kinase by phosphorylating conserved residues (Ser1064, Ser1074 and Thr1075) within the CORB GTPase domain

Leucine-wealthy-repeat-kinase 1 (LRRK1) and it is homolog LRRK2 are multidomain kinases aquiring a ROC-CORA-CORB that contains GTPase domain and phosphorylate distinct Rab proteins. LRRK1 lack of function mutations make the bone disorder osteosclerotic metaphyseal dysplasia, whereas LRRK2 missense mutations that enhance kinase activity cause Parkinson’s disease. Previous work recommended that LRRK1 although not LRRK2, is activated using a Protein Kinase C (PKC)-dependent mechanism. Ideas show phosphorylation and activation of LRRK1 in HEK293 cells is blocked by PKC inhibitors including LXS-196 (Darovasertib), a substance which has joined numerous studies. We show multiple PKC isoforms phosphorylate and activate recombinant LRRK1 inside a manner reversed by phosphatase treatment. PKCa suddenly doesn’t activate LRRK1 by phosphorylating the kinase domain, but rather phosphorylates a cluster of conserved residues (Ser1064, Ser1074 and Thr1075) located inside a region from the CORB domain from the GTPase domain. These residues are situated in the equivalent region from the LRRK2 DK helix reported to stabilize the kinase domain aC-helix within the active conformation. Thr1075 represents an ideal PKC site phosphorylation motif and it is mutation to Ala, blocked PKC-mediated activation of LRRK1. A triple Glu mutation of Ser1064/Ser1074/Thr1075 to imitate phosphorylation, enhanced LRRK1 kinase activity ~3-fold. From analysis of accessible structures, we postulate that phosphorylation of Ser1064, Ser1074 and Thr1075 activates LRRK1 your clients’ needs interaction and stabilization from the aC-helix around the kinase domain. This research provides new fundamental insights in to the mechanism controlling LRRK1 activity and divulges a singular unpredicted activation mechanism.