Researchers have recently found that these proteins are responsible for cleaving components of the extracellular matrix and suggested that they could be important players in a number of remodeling processes that involve Atropine sulfate collagen fiber deposition. Do these proteins play a role in the remodeling processes of silk fiber deposition? Genetic engineering works have shown similarities between spidroin fibers and collagen fibers. This hypothesis of remodeling function for meprins must be confirmed experimentally, although it is not unlikely because this process may help recycle unused web fibers. Some have reported that spiders eat their own webs to recover the energy spent on the spinning process, and members of G. cancriformis rebuild their webs daily. We found a number of spider silk proteins expressed in the two transcriptomes analyzed. For Actinopus spp., we found only putative homologs to of the common mygalomorph spidroins. Therefore, we were not able to find clear evidence that MaSps is present in this mygalomorph spider. Although a transcriptome project is always an incomplete sample of genes, we would expect to find the expression of these proteins in the broad analysis conducted here. Recently, a spidroin that presented clear similarities to MaSp2 from the orbweaving araneoid clade was identified in the mygalomorph spider A. juruensis, and phylogenetic analysis confirmed the similarities by placing this gene within the orbicularian MaSp2 clade. The absence of MaSps, however, is not completely unexpected because Actinopus is a genus of spiders with the retention of many primitive characters, including their spinning structures. It is conceivable that the MaSp gene family originated after the split between the Actinopodidae and Theraphosidae families of the Mygalomorphae clade. Another possible explanation for the absence of MaSps in Actinopus spp. is related to their ecological niches. The Amazonian Cinoxacin Avicularia spp. prefer an arboreal habitat, and their nests are made of large leaves held together by silk in the foliage of trees. In contrast, Actinopus spp. is a trapdoor spider and only uses its web to build burrows or egg sacs, which require a lower mechanical strength from the silk. Interestingly, this difference also highlights the importance of gene duplication for the evolution of new biological functions. On the other hand, we were able to verify the presence of a vast repertoire of spidroin families expressed in the complex spinning apparatus of G. cancriformis. Several characteristics revealed by our analysis indicate that members of G. cancriformis are particularly complex organisms, from the standpoint of not only anatomical characteristics but also molecular ones. For example, antisense transcripts of genes responsible for encoding spidroin sequences in G. cancriformis have been found, and 44 gene families presented a KOG ratio over four when compared to Actinopus spp. We related the number of transcripts found and the size of different glands to the overall spinning gland complex. A high number of transcripts were identified from the MaSp family, including MaSp1 and MaSp2, which are putatively expressed in the major ampullate glands, followed by the tubulliform spidroins, which are expressed in the relatively large tubulliform glands. Products of smaller glands like the flagelliform, pyriform and aciniform were also identified here. However, the expression of each spidroin must be more accurately measured before assigning the production of a specific protein to a specialized gland. We were able to observe the repetitive sequence of silk proteins from G. cancriformis.