ISP1-Anchored Polarization of GCβ/CDC50A Complex Initiates Malaria Ookinete Gliding Motility

Han Gao,Zhenke Yang,Xu Wang,Pengge Qian,Renjie Hong,Xin Chen,Xin-Zhuan Su,Huiting Cui,Jing Yuan

doi:10.1016/j.cub.2018.06.069

Abstract

Ookinete gliding motility is essential for penetration of the mosquito midgut wall and transmission of malaria parasites. Cyclic guanosine monophosphate (cGMP) signaling has been implicated in ookinete gliding. However, the upstream mechanism of how the parasites activate cGMP signaling and thus initiate ookinete gliding remains unknown. Using real-time imaging to visualize Plasmodium yoelii guanylate cyclase β (GCβ), we show that cytoplasmic GCβ translocates and polarizes to the parasite plasma membrane at "ookinete extrados site" (OES) during zygote-to-ookinete differentiation. The polarization of enzymatic active GCβ at OES initiates gliding of matured ookinete. Both the P4-ATPase-like domain and guanylate cyclase domain are required for GCβ polarization and ookinete gliding. CDC50A, a co-factor of P4-ATPase, binds to and stabilizes GCβ during ookinete development. Screening of inner membrane complex proteins identifies ISP1 as a key molecule that anchors GCβ/CDC50A complex at the OES of mature ookinetes. This study defines a spatial-temporal mechanism for the initiation of ookinete gliding, where GCβ polarization likely elevates local cGMP levels and activates cGMP-dependent protein kinase signaling.

Highlights

The spread of a malaria parasite relies on its successful development in a mosquito vector
Mechanical force produced by the actomyosin motor is converted to backward movement of CTRP, generating forward gliding motility that acts as a driving force for invasion of host cells [5]. 30–50-cyclic guanosine monophosphate, cGMP-dependent protein kinase G (PKG), phosphodiesterase delta (PDEd), and guanylate cyclase beta (GCb) have been shown to be crucial for ookinete motility in the rodent malaria parasite Plasmodium berghei [6,7,8]
GCb Is Polarized at a Unique Extrados Site in Mature Ookinetes To dissect the roles of GC proteins in ookinete gliding, we first investigated the expression of GCa and GCb in ookinetes

Summary

Introduction

The spread of a malaria parasite relies on its successful development in a mosquito vector. Within 12–20 hr, the zygotes further differentiate into crescent-shaped motile ookinetes that penetrate the midgut epithelium and develop into oocysts, each containing hundreds of sporozoites. Mature sporozoites invade the salivary glands and infect a new vertebrate host when the mosquito bites again [1]. Gliding motility of malaria parasites is essential for ookinete penetration of mosquito midgut wall and sporozoite migration to salivary gland for transmission from mosquito to vertebrate host. Coordinated activities of GCb (synthesizes cGMP) and PDEd (hydrolyzes cGMP) regulate cGMP levels that activate PKG, leading to phospholipase C (PLC)/inositol triphosphate (IP3)-mediated Ca2+ release, phosphorylation of multiple proteins in the glideosome, and initiation of ookinete gliding [7,8,9]. How the parasite initiates cGMP signaling upstream of PKG and regulates ookinete gliding remains unknown

Methods

Results

Discussion

Conclusion