Listeria monocytogenes derived ActA (“act-A”) induces the assembly of Arp2/3 (“arp-2-3”) complexes that promote polymerization of this protein in “comet tails.” For 10 points each:
[10e] Name this protein that forms microspikes at the lamellipodia edges of migrating cells. MreB (“M-R-E-B”) is the prokaryotic analog of this protein, whose microfilament structures bind to myosin heads during muscle contraction.
ANSWER: actin [accept F-actin or G-actin]
[10h] ActA acts as a mimic for an actin nucleation promoting factor mutated in this syndrome. This X-linked doubly eponymous syndrome is alternatively named after a triad of eczema, thrombocytopenia, and immunodeficiency.
ANSWER: Wiskott–Aldrich syndrome [or WAS; accept Wiskott–Aldrich syndrome protein or WASp; prompt on X-linked thrombocytopenia or XLT; prompt on X-linked congenital neutropenia or XLN]
[10m] In the “zipper” mechanism, Listeria invades host cells by binding surface internalins, which in turn interact with the epithelial form of this protein. Defects in these calcium-dependent cell adhesion proteins can trigger cancer cell metastasis.
ANSWER: cadherins [accept cadherin-1; accept E-cadherins or T-cadherins or P-cadherins; prompt on cads or E-cads or T-cads or P-cads]
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