Please answer each multiple choice question, and kindly leave a brief explanatio
ID: 35037 • Letter: P
Question
Please answer each multiple choice question, and kindly leave a brief explanation for each answer.
52. Which of the following is the most likely target molecule exploited by a pathogen if neutrophils unable to kill the bacteria after phagocytosis 53. The correct sequence of molecules activated during reorganization of actin cytoskeleton is 54. Which of the following is the most likely target molecule exploited by a pathogen, which interferes with initiation of actin filament polymerization in the cell? 55. Which of the following is not correct for Yersinia invasion? 56. Why adherence of Yersinia pseudotuberculosis and Listeria monocytogenes to host cells is independent of the actin cytoskeleton although host cell cytoskeleton is perturbed during invasion?Explanation / Answer
52.Which of the following is the most likely target molecule exploited by a pathogen if neutrophils unable to kill the bacteria after phagocytosis. A)Rho b)Rac c) Cdc42 d)Rab e) All of the above
Answer is e) All of the above. Many bacterial pathogens use specialized secretion systems to deliver proteins into host cells that subvert signaling pathways controlling membrane transport.Bacterial factors will exploit eukaryotic Rho GTPase signaling cascades, Rac, Rab and Cdc42 to evade phagocytosis.
53.The correct sequence of molecules activated during reorganization of actin cytoskeleton
Answer is a) Cdc42; N-WASP; Arp2/3; Profilin
The Arp2/3 complex is essential in initiation of actin assembly. The RhoG, Rac1 and Cdc42 activates N-WASP and which then complexed with the monomers of globular acting and Arp2/3, which initiates nucleation of actin and polymerization into actin filaments.. The COOH terminal domain of N-WASP containing verproline homology region will interact with G-actin in a profiling.
54. Which of the following is the most likely target molecule exploited by a pathogen, which interferes with initiation of actin filament polymerization in the cell?
a)Ras b)ARF6 c)N-WASP d) Arp2/3 e)Cdc42
Answer is d)Arp2/3. When the Arp2/3 complex is activated by nucleation-promoting factors (NPFs), nucleates branched actin networks and these NPFs can be recruited to the plasma membrane and activated by Rho-family GTPases finally ruffles and phagocytic cups. So, most pathogens gaining access into the cell signal to the Arp2/3 complex during their entry. Actin rearrangement will facilitate the entry of the pathogen inside the cell.
55) Which of the following is not correct for Yersinia invasion?
a)Yersinia utilizes an invasin that is an outer membrane protein on the bacteria
b)Yersinia utilizes an invasin that contains a RGD motif that binds to host cell integrin
c)Yersinia utilizes an invasin that has higher affinity for host cell integrin than native ligand in the tissue
d)Yersinia utilizes an invasin that induces cell signaling in the host cell through integrin oligomerization and clustering
Answer is d) Yersinia utilizes an invasin that induces cell signaling in the host cell through integrin oligomerization and clustering. This statement is incorrect. As Yersinia will not use invasion to induce cell signaling.