Selectivity of yolk protein uptake: Comparison of vitellogenins of two insects

Kunkel, Joseph G.; Pan, M. L.

doi:10.1016/0022-1910(76)90248-1

Cited by 95 publications

(43 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These results agree with those of Kunkel and Pan [14], who showed that 18s Vt, but not 33s Vt, is endocytosed by the oocytes of B. germmica. panel B, shows the effects on uptake of both Vts and compares these data with the endocytosis of untreated Vt and [1251]-~-galactosidase, the latter employed to measure nonspecific bulk pinocytosis [22].…”

Section: Effects Of Modifying Vitellin On Its Uptake By Oocytes In Vivosupporting

confidence: 95%

See 1 more Smart Citation

Experimental modifications of an insect vitellin affect its structure and its uptake by oocytes

Gochoco

Kunkel

Nordin

1988

Arch Insect Biochem Physiol

Self Cite

View full text Add to dashboard Cite

The 18s and 33s vitellins (Vts) of Blattella germanica were subjected to periodate oxidation and digestions with a-mannosidase, endo-0-Nacetylglucosaminidase H (endo-H), and trypsin to study their effects on Vt structure and function. Periodate oxidation caused 335 Vt to dissociate to a form that cosedimented with 18s Vt upon glycerol gradient centrifugation but had no effect on the sedimentation of 18s Vt. This result implicates the oligosaccharides in stabilization of the 33s structure. Incubation of 18s and 33s Vts with a-mannosidase and endo-H revealed that the oligosaccharides of both Vts are largely shielded from attack by both glycosidases. However, the carbohydrate of 18s Vt was 3 to 5 times more susceptible to both enzymes, suggesting that the 18s to 33s transition results in decreased accessibility of the oligosaccharides to both glycosidases. Short-term exposure of 18s and 33s Vts to trypsin resulted in limited hydrolysis; the M,102,000 subunit of each form was cleaved with an M,79,000 peptide as a major product. However, the sedimentation properties of the Vts and their relative susceptibilities to a-mannosidase were unchanged; therefore while the M,102,000 subunit of the Vt i s vulnerable to trypsin, it retains i t s higher-order structure after limited digestion. Endocytosis of radiolabelled 18s Vt by oocytes in vivo decreased about 15-fold after its modification by periodate and sixfold after treatment with a-mannosidase. Limited trypsin digestion also severely diminished its uptake. All injected radioactivity of unmodified 18s and 33s Vts could be recovered from either the hemolymph or ovaries of recipient females.However, modified Vts were taken up from the hemolymph primarily by cells of the pericardium and the fat body, suggesting that these organs participate in a clearance mechanism that recognizes "damaged" Vt molecules.

show abstract

Section: Effects Of Modifying Vitellin On Its Uptake By Oocytes In Vivosupporting

confidence: 95%

“…Vitellin was isolated and purified as described previously [7,14] with 1.7 mM PMSF present in all solutions. They were concentrated when necessary for some experiments in dialysis bags against dry carboxymethyl cellulose at room temperature or by using microconcentrators.…”

Section: Isolation and Purification Of Vtmentioning

confidence: 99%

Experimental modifications of an insect vitellin affect its structure and its uptake by oocytes

Gochoco

Kunkel

Nordin

1988

Arch Insect Biochem Physiol

Self Cite

View full text Add to dashboard Cite

show abstract

“…TLCK and TPCK, inhibitors of trypsin and chymotrypsin-like serine proteases respectively (31), also inhibit some cysteine proteases (32). Protease-free Vt-When Vt is prepared by ion exchange chromatography of day 0 yolk (33), it retains some acid-activable protease, which made it unsuitable for in vitro enzyme action pattern studies (described below). Vt isolated by Sephacryl S-300 chromatography of day 0 yolk (see Fig.…”

Section: Resultsmentioning

confidence: 99%

A Cysteine Protease That Processes Insect Vitellin

Liu¹,

McCarron²,

Nordin

1996

Journal of Biological Chemistry

View full text Add to dashboard Cite

A cysteine protease that initiates degradation of vitellin (Vt) in the orthopteran Blattella germanica, and its proprotease precursor, were purified from yolk and partially characterized. The protease, purified 300-fold, contains three peptides of M r 27,000, 29,000, and 31,000. A comparison of the purified enzyme's action pattern on Vt in vivo and in vitro confirmed its role in Vt processing. Protease-deficient yolk (day 0 postovulation) contained peptides of M r 35,500, 37,000, 39,000, and 41,000, which were absent from yolk with protease activity. These were replaced by three peptides of approximately M r 29,000, at days 2-3, the same time in development that protease expression and acidification of yolk granules occur (Nordin, J. H., Beaudoin, E. L., and Liu, X. (1991) Arch. Insect Biochem. Physiol. 18, 177-192). Acidification of purified proprotease converted it to three peptides of approximately M r 29,000 with cysteine protease activity. This conversion also required participation of a cysteine protease. Activated proprotease had the same pH activity profile, susceptibility to inhibitors, and cathepsin classification (L) as the protease. These results indicate that the Vt-processing protease is derived from a proprotease, which is activated in vivo by a developmentally regulated decrease in intragranular pH.

show abstract

“…3, lane 3). Vt peptides were also labeled non-specifically by this probe (Liu et al, 1996), probably at their cysteine residues (Kunkel and Pan, 1976).…”

Section: Preparation Of Proprotease-free Affinity Ligands From Yolk Pmentioning

confidence: 99%

Localization of the proenzyme form of the vitellin-processing protease inBlattella germanica by affinity-purified antibodies

Liu

Nordin

1998

Arch. Insect Biochem. Physiol.

View full text Add to dashboard Cite

Selectivity of yolk protein uptake: Comparison of vitellogenins of two insects

Cited by 95 publications

References 38 publications

Experimental modifications of an insect vitellin affect its structure and its uptake by oocytes

Experimental modifications of an insect vitellin affect its structure and its uptake by oocytes

A Cysteine Protease That Processes Insect Vitellin

Localization of the proenzyme form of the vitellin-processing protease inBlattella germanica by affinity-purified antibodies

Contact Info

Product

Resources

About