CASK (Calcium/calmodulin-dependent serine kinase) is a membrane-associated guanylate kinase (MAGUK) found in metazoans.
Posted: Tue May 17, 2022 3:45 pm
CASK (Calcium/calmodulin-dependent serine kinase) is a
membrane-associated guanylate kinase (MAGUK) found in metazoans. It
is in the same gene family as PSD-95 and has PDZ, SH3, and
non-catalytic guanylate kinas domains used for binding to other
proteins at cell junctions, but it also has a
Calcium/Calmodulin-dependent kinase (CaMK) domain which it uses
phosphorylate targets. How might the PSD-95-like ancestor of CASK
have obtained the CaMK domain? Select the best answer.
a) A frame-shift mutation in the 5’-UTR resulted in the
formation of a new protein domain in front of the existing start
codon.
b) A transposon near a gene encoding a protein which contained a
CaMK domain “jumped” into the 5’-UTR of the MAGUK gene, taking with
it a chunk of neighboring DNA including the coding sequence for the
CaMK domain.
c) Bacteriophage virus packaged up some genomic DNA containing
the CaMK coding sequence during viral replication, and this
sequence was incorporated into the MAGUK gene of another cell after
bacteriophage infection.
d) All of the above are equally likely explanations for the
origin of the CASK gene in metazoans.
Which at this point I know that (A) and (D) are wrong
membrane-associated guanylate kinase (MAGUK) found in metazoans. It
is in the same gene family as PSD-95 and has PDZ, SH3, and
non-catalytic guanylate kinas domains used for binding to other
proteins at cell junctions, but it also has a
Calcium/Calmodulin-dependent kinase (CaMK) domain which it uses
phosphorylate targets. How might the PSD-95-like ancestor of CASK
have obtained the CaMK domain? Select the best answer.
a) A frame-shift mutation in the 5’-UTR resulted in the
formation of a new protein domain in front of the existing start
codon.
b) A transposon near a gene encoding a protein which contained a
CaMK domain “jumped” into the 5’-UTR of the MAGUK gene, taking with
it a chunk of neighboring DNA including the coding sequence for the
CaMK domain.
c) Bacteriophage virus packaged up some genomic DNA containing
the CaMK coding sequence during viral replication, and this
sequence was incorporated into the MAGUK gene of another cell after
bacteriophage infection.
d) All of the above are equally likely explanations for the
origin of the CASK gene in metazoans.
Which at this point I know that (A) and (D) are wrong