A signalling cascade for Ral

Figures & data

Table 1. A table of conserved signalling molecules in mammals, Drosophila and C. elegans.

Mammals	Drosophila	C. elegans
HGK/MAP4K (4,6–8)	misshapen (msn)	MIG-15
MAP4K (1–3,5)	happyhour (hppy)	GCK-2
JNK (1–3)	basket (bsk)	JNK-1
MAP3K9/MLK	slipper (slpr)	MLK-1
p38 (α,β,γ,δ)	p38	PMK-1
Ras (H,N,K)	ras	LET-60
Ral (A/B)	ral	RAL-1
Exo84	exo84	EXOC-8
Notch (1,2,3)	Notch	LIN-12

Figure 1. C. elegans VPC fate patterning and signalling cascades in the Ras and Notch signalling network. A) Developmental patterning of VPC fates. The anchor cell (AC) induces six equipotent VPCs to form the 3°-3°-2°-1°-2°-3° pattern of cell fates. EGFR>Ras>Raf>MEK>ERK MAP kinase cascade induces 1° fate. Through sequential induction, 1° cells induce immediate neighbours to assume 2° fate by secreting DSL ligands for the Notch receptor. The graded EGF signal also triggers activation of Ras>RalGEF>Ral to induce 2° fate in neighbouring VPCs.

Figure 2. Potential components of the Ral signalling network. Regulatory relationships of Ral and functionally related proteins in apoptosis during bristle development in Drosophila as inferred by mutant interactions with hypomorphic mutations in Ral [33].

Figure 3. Regulatory relationships of the Ras>RalGEF>Ral>Exo84>GCK-2>MLK-1>PMK-1 cascade that promotes 2° VPC fate in support of Notch during C. elegans VPC fate patterning. The Ral>GCK-2 cascade was ordered through epistatic interactions, while MIG-15 appears to function in parallel to inhibit both 1°- and 2°-promoting signals [37].

Balakireva M, Rosse C, Langevin J, et al. The Ral/exocyst effector complex counters c-Jun N-terminal kinase-dependent apoptosis in Drosophila melanogaster. Mol Cell Biol. 2006;26(23):8953–8963.

 PubMed Web of Science ®Google Scholar

Shin H, Kaplan REW, Duong T, et al. Ral signals through a MAP4 Kinase-p38 MAP Kinase Cascade in C. elegans cell fate patterning. Cell Rep. 2018;24(10):2669–2681. e2665.

 PubMed Web of Science ®Google Scholar