Although we did not detect a direct correlation between Lasp-1 expression and the recruitment of MT1-MMP-containing vesicles to podosomes, our results are consistent with the idea that Lasp-1 may be important for the local release of lytic enzymes at matrix degrading podosomes in macrophages. In summary, our study shows that Lasp-1 is a novel component of the podosomal ring structure. Although Lasp-1 is recruited to podosomes at early stages of their assembly, the protein is probably not necessary for the initiation of podosome formation. However, Lasp-1 is involved in of the regulation of several podosome parameters including size, number and lifetime and also regulates the matrix degradation capacity of podosomes. These activities reveal Lasp-1 as a novel important regulator of podosomes and also point to Lasp-1 as a potential target for the modulation of invasive cell migration. The enzyme hydrolyzes ATP and forms an electrochemical proton gradient on the PM and drives the transport of basic nutrients across the PM. As has been shown previously, Pma1 consumes up to 20% of cellular ATP and, not surprisingly, its activity is under strict control. The regulation of Pma1 activity was shown for the first time by Serrano, who discovered that incubation with glucose resulted in a reversible many-fold enhancement of the enzyme��s activity, a decrease in K m, and an increase in Vmax. The sugars utilized via the glycolytic pathway were shown to lead to the enhancement of the enzyme��s activity. Sugars metabolized through other SRPIN340 pathways, as well as nonmetabolized glucose analogs, did not result in any enhancement. Quite recently, it has been shown that glucose-dependent Pma1 activation is accompanied by double phosphorylation of the enzyme at the Ser-911 and Thr-912 positions. Phosphorylation of these two residues is thought to eliminate the inhibitory effect of the enzyme��s C-terminus on the ATP-hydrolyzing domain. It is possible that the process of Pma1 phosphorylation involves protein kinase C, the activation of which is associated with the transport and phosphorylation of glucose. Electron cryomicroscopy and crystallographic analysis were used previously to determine the tertiary and quaternary structure of the enzyme. Pma1 was shown to form detergentresistant hexamers, within which the monomers contact each other at the levels of both the transmembrane and cytoplasmic domains. Another important finding was that the hexameric structure has internal mobility and becomes more closely packed under substrate binding. As has been shown, some membrane proteins have to be associated with lipid rafts for correct incorporation into the plasma membrane. To be delivered to and incorporated into the plasma membrane, Pma1 must also form a complex with sphingolipid. In the cells with disturbed sphingolipid synthesis, the newly synthesized native Pma1 has been shown to be routed, instead of to the PM, to the vacuole where it is degraded. Previous experiments with PMA1-GFP have allowed direct visualization of the raft compartmentalization of Pma1. A recently proposed model of membrane organization has suggested that all membrane proteins are contained both in the rafts and in the nonraft lipid domains and separated by vast protein-free lipid regions. All protein-lipid ����islands���� are also thought to be bound to Isoetharine Mesylate cytoskeleton elements. This idea has aroused particular interest due to the finding of an acetylated tubulin-Pma1 complex in glucose-starved yeast and its dissociation under glucose addition.