The SpoIIQ-SpoIIIAH complex of XXXX controls forespore engulfment and late stages of gene expression and spore morphogenesis.

@entity8862 @entity70769 @entity219 @entity3689 @entity2718 @entity3881
UNASSIGNED: Engulfment of the forespore by the mother cell is a universal feature of endosporulation. In @entity3881 , the forespore protein SpoIIQ and the mother cell protein SpoIIIAH form a channel, essential for endosporulation through which the developing spore is nurtured. The two proteins also form a backup system for engulfment. Unlike in @entity3881 , SpoIIQ of @entity2718 has intact LytM @entity219 -binding motifs. We show that spoIIQ or spoIIIAH deletion mutants of @entity2718 result in anomalous engulfment, and that disruption of the SpoIIQ LytM domain via a single @entity3689 substitution ( @entity70769 ) impairs engulfment differently. SpoIIQ and SpoIIQ( @entity70769 ) interact with SpoIIIAH throughout engulfment. SpoIIQ, but not SpoIIQ( @entity70769 ) , binds @entity8862 , and metal absence alters the SpoIIQ-SpoIIIAH complex in vitro. Possibly, SpoIIQ( @entity70769 ) supports normal engulfment in some cells but not a second function of the complex, required following engulfment completion. We show that cells of the spoIIQ or spoIIIAH mutants that complete engulfment are impaired in post-engulfment, forespore and mother cell-specific gene expression, suggesting a channel-like function. Both engulfment and a channel-like function may be ancestral functions of SpoIIQ-SpoIIIAH while the requirement for engulfment was alleviated through the emergence of redundant mechanisms in @entity3881 and related organisms. This article is protected by copyright. All rights reserved.
