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

ABSTRACT: Leucine-rich-repeat-kinase 1 (LRRK1) and its homologue LRRK2 are multidomain kinases possessing an atypical ROC-CORA-CORB containing GTPase domain and phosphorylate distinct Rab proteins. LRRK1 loss of function mutations cause the bone disorder osteosclerotic metaphyseal dysplasia, whereas LRRK2 missense mutations that enhance kinase activity cause Parkinson’s disease. Previous work suggested that LRRK1 but not LRRK2, is activated via a Protein Kinase C (PKC)-dependent mechanism. Here we demonstrate that phosphorylation and activation of LRRK1 in HEK293 cells is blocked by PKC inhibitors including LXS-196 (Darovasertib), a compound that has entered human clinical trials. We show multiple PKC isoforms phosphorylate and activate recombinant LRRK1 in a manner reversed by phosphatase treatment. PKCα phosphorylates LRRK1 at cluster or conserved residues (Ser1064, Ser1074 and Thr1075) located within a region of the CORB domain that lies at the equivalent region of the LRRK2 DK helix that is reported to stabilize the kinase domain αC-helix in the active conformation. Thr1075 lies within an optimal PKC site phosphorylation motif and its mutation, blocked PKC mediated activation of LRRK1. A triple Glu mutation of Ser1064/Ser1074/Thr1075 to mimic phosphorylation, enhanced LRRK1 kinase activity ~3-fold. From analysis of available structures, we postulate that phosphorylation of Ser1064, Ser1074 and Thr1075 could activate LRRK1 promoting interaction of these residues with the C-helix on the kinase domain. This study provides fundamental insights into the mechanism controlling LRRK1 activity.

INSTRUMENT(S): Orbitrap Exploris 240

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Protein Kinase Regulator Activity

DISEASE(S): Osteoporosis

SUBMITTER: Raja Sekhar Nirujogi  

LAB HEAD: Dario R. Alessi

PROVIDER: PXD034420 | Pride | 2022-09-02

REPOSITORIES: Pride